What do i hate about bitcoin? Well. There's nothing i dislike about the things, about the process of bitcoin. But theres one thing that i would suggest to, its about if making transactions, i think it take a time to have transactions but overall, theres nothing to change, i love bitcoin.
i do not think that people hate to bitcoin because bitcoin is very useful currency and bitcoin transaction is very faster and its transaction fees is very much lower and you are right there is a lot of people love to bitcoin.
but there is something that make people not happy about bitcoin ,
some people do not like a feature of double spending when you do it it is like you cancel the transaction to nowhere ,
also when you send bitcoin to wrong address it is considered as donation noone can help you ,
and a lot of other things make people unhappy about bitcoin but so far it less than the benefit itself.