We can't buy something with Bitcoin quickly

[glerand]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

[spazzdla]

Depends on the merchant, the guy in my city(a baker) is fine with an unconfirmed tx.  For sure there will be people that double spend as people are serious piles of shit, but that is just like the losers that dine and dash, steal from vending machines,  etc.  Business just eat the costs of human bile.

[glerand]

Depends on the merchant, the guy in my city(a baker) is fine with an unconfirmed tx.  For sure there will be people that double spend as people are serious piles of shit, but that is just like the losers that dine and dash, steal from vending machines,  etc.  Business just eat the costs of human bile.

You can double spent a transaction with a phone wallet?
But if you show your wallet, and the merchant verify that you send the transaction without any problem, and he find it in his wallet (without confirmations, but if you set a high fee, it will confirm soon).

[wantjokull]

The high fees is always a good option and with that you can confirm the transaction with upto 10 minutes. But looking at the current fees which are very high it is not really possible to pay that everyone you buy your coffee. What you can do is you can initiate the transaction and once the merchant see incoming transaction you can let him confirm that manually with blockchain. That would be easiest way to grab your coffee quickly. If merchant is not that trusting then you can pay fees and find another merchant for the same product. Haha. I think that would be quicker next time. Well we can just hope for now the problems regarding faster transaction will be overcome very soon. Next time we may not wanna seat and see our coffee getting cold. :-)

[LodisMcguire]

In this time,bitcoin is not convenient to use for daily expense
It's like gold,you are not spend gold to buy some trivial need
Maybe in the future,after the problem of long transaction and high fees has been solved,we can use it for daily matters

[DannyHamilton]

You can double spent a transaction with a phone wallet?

It's possible, but it isn't easy.  Also, an intelligent merchant can determine if the transaction is high-risk or not.  If it is low risk, then they may be willing to accept the risk and let you leave with your product.  If it is high-risk, they may require that you collect your product after confirmation.

But if you show your wallet, and the merchant verify that you send the transaction without any problem, and he find it in his wallet (without confirmations, but if you set a high fee, it will confirm soon).

If you use a high fee, you are probably not going to buy a coffee (the fee will be a significant percentage of the purchase cost).  The merchant doesn't need to see your wallet.  The merchant only needs to monitor the network and determine if the transaction is high-risk or not.  Then the merchant can make a decision on what risk they are willing to accept and how they want to run their business.

[glerand]

The high fees is always a good option and with that you can confirm the transaction with upto 10 minutes. But looking at the current fees which are very high it is not really possible to pay that everyone you buy your coffee. What you can do is you can initiate the transaction and once the merchant see incoming transaction you can let him confirm that manually with blockchain. That would be easiest way to grab your coffee quickly. If merchant is not that trusting then you can pay fees and find another merchant for the same product. Haha. I think that would be quicker next time. Well we can just hope for now the problems regarding faster transaction will be overcome very soon. Next time we may not wanna seat and see our coffee getting cold. :-)

Even with a high fee, your transaction can take up to 30 minutes, one hour sometimes, depends on when a block will be founded by a pool.
I also saw that some Altcoins like Dogecoin have very fast transactions, not like Bitcoin.

[Barcode_]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

That is the problem that bitcoin have been facing at the moment, high transaction fees, slow confirmations on the blockchain unless the user selects a high priority fees, but I doubt there would be anyone who are willing to fork out additional money just for purchasing one coffee. Maybe it would be a good idea to stop using bitcoin for small transaction at the moment, until the confirmation about the segwit or fork on 1st august.

[taxmanmt5]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

I can buy nearly anything around here in the same amount of time that it takes to use FIAT.  Just have to know what you are doing and how to do it. The future will see something like Bitcoin, but combined with a system like Paypal, where you are loading an account with your coins and that account waits on the transactions to confirm and the merchants will trust that service.

[2girls]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

I can buy nearly anything around here in the same amount of time that it takes to use FIAT.  Just have to know what you are doing and how to do it. The future will see something like Bitcoin, but combined with a system like Paypal, where you are loading an account with your coins and that account waits on the transactions to confirm and the merchants will trust that service.

It is pretty certain that something is going to ruin the decentralized qualities of Bitcoin with a system like that.  It is fear based and greed based and is sold on the fact that people cannot wait a few minutes for things to happen, they must have them NOW

[Despacito]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

The society and the community could not adopt bitcoin as a whole. We still ned more time for society to adopt bitcoin in all means. But at the end, this will be much different from the current position of it. It's becomming more common every single day.

[agustina2]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

To deal with that incident, Im sure those merchants knows the current status of bitcoin network. No way they will just make bitcoin payment as one of their payment method if they are not aware to the status of bitcoin.

And why you will just show your wallet? Just send them even without confirmation as long as it was on the network. At least that is the best way. To deal with customers that will pay on bitcoin, it's obvious that there are things the owner will do with the current status of slow confirmation.

[Yakamoto]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

Merchants can see that you've actually sent the Bitcoin since, assuming their wallet is synced and actively connected to the blockchain, the transaction will show up in the wallet and they would just have to wait for the transaction to be confirmed before they actually own the Bitcoin you sent. Most people wouldn't double-spend anyways so there would be a fair amount of confidence from merchants for something like this.

[Ethan_Locke]

If these block sizes are increase we shouldn't have any problems with that =]

[jorneyflair]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

Right now, bitcoin is not really convenient and good for everyday use, mostly due to the long confirmation times and high transaction fees. No one wants to pay a 10 dollar fee for 50 dollar fee, just for it to speed up. For most shops that accept bitcoin right now, the shop owner may ask to see your wallet in case you double spend, but it is mostly up to the manager to determine whether to accept it or not.
 
For example, say you are purchasing a TV or something that is in the 4 digits. The merchant will probably not let you give your word that you didn’t double spend. They will probably ask you to pay you a higher transaction fee that their payment could be received within that hour. It is mostly up to the intelligence of the merchant and if he is willing to take that risk.

[Gens09]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

Actually you can buy in bitcoin quickly in a store and it is i guess very easy to use  because you will you can the qr code to pay what you buy and thats it your already paid but all that matter is the transaction speed not all bitcoin wallet send money in a seconds today some bitcoin wallet takes a lot of hours and even days.

[Russlenat]

For exemple, I go to a coffee shop, I buy a coffee, then I pay with Bitcoin, we have to wait for a confirmation, no? or the merchant will just trust me if I show my wallet?
How can we be sure that it's not a double spent transaction or something else?

Actually you can buy in bitcoin quickly in a store and it is i guess very easy to use  because you will you can the qr code to pay what you buy and thats it your already paid but all that matter is the transaction speed not all bitcoin wallet send money in a seconds today some bitcoin wallet takes a lot of hours and even days.

That's true! bitcoin payment need network confirmation so it can delay the transaction and it is not recommended to buy goods in instant, just cash-out first your bitcoin and convert to fiat.

[clickerz]

As of now, this is the problem with Bitcoin, It takes time for a transaction to confirmed,. You have to raised the charges or fees to be prioritized in the cue. As of now also, ETH suffers congestion also.Speed of transaction is the issue on most of the cryptos now, because of the high demand and bulk of transaction being processed. Hope this new Segwit? will help bitcoin.

[TimeTeller]

Right now, bitcoin is not really convenient and good for everyday use, mostly due to the long confirmation times and high transaction fees. No one wants to pay a 10 dollar fee for 50 dollar fee, just for it to speed up. For most shops that accept bitcoin right now, the shop owner may ask to see your wallet in case you double spend, but it is mostly up to the manager to determine whether to accept it or not.
 
For example, say you are purchasing a TV or something that is in the 4 digits. The merchant will probably not let you give your word that you didn’t double spend. They will probably ask you to pay you a higher transaction fee that their payment could be received within that hour. It is mostly up to the intelligence of the merchant and if he is willing to take that risk.

The situation presented is very true.
So the bottomline is, it's up to the user and the merchant - how they deal with such situation regarding btc transactions.
For right now, there are still some bottlenecks with BTC transactions, you just need to weigh the advantages & disadvantages brought by utilizing the digital currency.

[coolstory]

If these block sizes are increase we shouldn't have any problems with that =]

It doesn't only depend on block size or transaction speed. There is a legal and adoption problem about bitcoin.