The most painful thing is what I'm going through right now. When I deposit to an exchange, but the exchange does not credit our deposit on the account. That exchange is a scam, stealing customers' money. Be careful of all of you. I lost almost $5000 recently. Even more so because the coin I intend to sell the price is getting up. You better trade on exchanges that have a good reputation.
I really haven't had a very bad experience in the crypto world, I've only ever lost because I released my tokens at a price that was just dropping. so never play on an exchange that is not well known if you don't want to take the risk. just wait for the right time.