The most frustrating stuff that bitcoin has is that when you are scammed by the other person or company. It is impossible for you to bring back your money because of the lack of incentives that we have. One great example is the Hash ocean. They scammed about 700+ thousand individuals and sadly, they cannot be traced or put into jail. Its because we dont have a legal protection against these people who dont give back the right services and payments that we should have. If a certain law will be established with regards to this problem. I think the bitcoin community will grow rapidly.
But really, really you belived it was mining and a legitimate business. at the rate of 1300% / year it is impossible for anybody to pay such ammount of money to customers and still keep their share.
Just make the calculation, buy a graphic card, mine the most profitable coin and you'll see you'll be far from that profit margin. Miracles may exist but are very-very rare.
I also had some BTC in HashOcean, i "invested" there knowing that it is a scam. I lost it because I got greedy, I've reinvested
Some scams pay off, some don't. Every ponzi has some winners and a lot of loosers. In my country some 20+ years ago was a good scam, you got 8 times your money in 3 months. Alot of people got rich, 98% lost it all.
BUT to the topic, my biggest problem is with confirmation time. Internet buying is fine, but in real life it is impossible to use it, you cannot buy a coffee when confirmation time is 30 minutes +.