has anyone ever had an unconfirmed transaction not going through?

[viboracecata]

It can sometime not get accepted by miners because of lower or no fees or maybe you try to spend it before confirmation somehow

Some bitcoin businesses accept instant deposit and payments without waiting confirmations but it is rare because they are probably losing money doing that.

If you buy some goods that worth $200, would you want to spend lots of work to produce a fake block?

If you the goods worth $200,00, merchants will wait for enough confirmations

[Beymond]

It can sometime not get accepted by miners because of lower or no fees or maybe you try to spend it before confirmation somehow

Some bitcoin businesses accept instant deposit and payments without waiting confirmations but it is rare because they are probably losing money doing that.

If you buy some goods that worth $200, would you want to spend lots of work to produce a fake block?

If you the goods worth $200,00, merchants will wait for enough confirmations

yep! no one will take risk over that big amount

[Kazimir]

It can sometime not get accepted by miners because of lower or no fees or maybe you try to spend it before confirmation somehow

Some bitcoin businesses accept instant deposit and payments without waiting confirmations but it is rare because they are probably losing money doing that.

Oh! never knew some do , AFAIK they atleast go for 1or 2 confirmations

No, pretty much any regular business that accepts Bitcoin, does so without ever waiting for any confirmations. Think about it - it'd be ridiculous to make a customer wait 10 minutes (or more) at the cash register before they can leave. They don't do that with credit cards either, and the chargeback risk is actually real there (unlike Bitcoin).

The exception is exchanges, they will typically await a few confirmations before updating your balance, but that's more like a deposit or cash transfer, not a case of live or real time paying for goods or services.

[countryfree]

I have had unconfirmed transactions not going through, but that was in my early BTC days, when I was experiencing with dust from faucets.

It's only natural for a merchant to wait for a transaction to be confirmed. The same thing used to happen in shops when a customer was requesting to pay by check. The shop would have called the bank to confirm the check was good. The problem was solved with shops not accepting checks anymore.

[networthsigns]

Yes  i hate the waiting time

[Beymond]

It can sometime not get accepted by miners because of lower or no fees or maybe you try to spend it before confirmation somehow

Some bitcoin businesses accept instant deposit and payments without waiting confirmations but it is rare because they are probably losing money doing that.

Oh! never knew some do , AFAIK they atleast go for 1or 2 confirmations

No, pretty much any regular business that accepts Bitcoin, does so without ever waiting for any confirmations. Think about it - it'd be ridiculous to make a customer wait 10 minutes (or more) at the cash register before they can leave. They don't do that with credit cards either, and the chargeback risk is actually real there (unlike Bitcoin).

The exception is exchanges, they will typically await a few confirmations before updating your balance, but that's more like a deposit or cash transfer, not a case of live or real time paying for goods or services.

That could happen , seeing the chances of double spend are quite low and here are no chargebacks

[ranochigo]

It can sometime not get accepted by miners because of lower or no fees or maybe you try to spend it before confirmation somehow

Some bitcoin businesses accept instant deposit and payments without waiting confirmations but it is rare because they are probably losing money doing that.

Why would it be rare? There are plenty of merchants with bitpay implementation accepting 0 confirmation transaction. A double spend is not as easy as you think. As long as you wait 30 seconds or so, connect to well connected nodes and the transaction is well propagated, a double spend is unlikely but not impossible.