Based up on my own experience then the most bad or sucks big time kind of exchange would be Yobit.net/com! Lets just exclude those totally been taken down by hacks and become scam but this exchange is shady as fuck big time.
1. No support/ They dont ever answer
2. Lots of shady coins
3. High House edge of their gambling games
4. Often wallet maintenance
Surprisingly this exchange is still running up to now and im surprised that there are still users who do make use of this
platform.
Oh yeaaah, these are the real annoying bits. I mean it is not easy to actually become this bad, like how the hell do you become an exchange and have zero support or very slow support? The shady coin part is a bit understandable, it does make the exchange not so much liked and all but those shady coins need a place to be exchanged anyway, so eventually one place will take it and that is why they will end up with something like a shitcoin here and there so that's fine, plus they are making profit from that as well.
There is nothing that can be done about the gambling part since if an exchange decided to go with gambling route, then they already gave up. Wallet maintenance is okay if you do it on different coins all the time because it would allow them to improve, but I have seen on the same coins back to back as well. All in all exchanges can be so annoying sometimes.