I have equal hate towards rogue and hunters, so i couldn’t pick between them. I hate rogue because they always play 10 cards every turn and shuffle everything back and forth doing nothing until their big otk moment.
I hate hunters because 99% of all hunters can only play aggro face smorc deluxe. And they NEVER trade, i can have a 25/1 minion on the board and he still chooses to go face with a 1/1 minion.
My favorite class to face gotta be priest, because i like long games. 
We should all strive to avoid being prejudiced against classes. Similarly I don’t think it’s that useful to have “mains” since it’s not World of Warcraft that we have to grind for gear to even start raiding and other such nonsense.
E.g. I had done the mistake to ‘hate’ warlocks and I was dusting their cards; now I wanted to play sludge at least for completing the achievements; now I have to wait for the rotation to properly play warlock.
Same. I used to think all druids were monsters and first prioritized dusting their stuff with extreme prejudice but now I see he’s just like Sloth from the Goonies. Yes he’s a giant but he’s generally a gentle one. They aren’t all Elise Starseeker or linecracker “insert platebreaker here for a free win” decks. Just the worst of them are. There’s actual goodness somewhere beneath all that armor
Priest needs to be deleted
Probably super unpopular but i dont enjoy facing demon hunter very much/s
I’ve lost count of the ways they have to copy their Aman’Thuls.
Don’t have a class i hate or love going against. As long as the person gives me a good match win or lose then i’m happy.
There was a week long poll for this very question on Twitter and surprise surprise Priest won the part for most hated and it wasn’t even remotely close.
Imagine obsessing about your petty hatreds and actually believing that you’re a decent person.