I kinda hate all of them, but the one I hate the least is probably winter. Spring is allergy season and merely existing is pain. Summer is too hot and bugs are everywhere, not to mention everybody in my family like to leave the doors open to the outside because "it's nice out" but refuse to acknowledge the fact that it lets in dozens of bugs and insects. Fall is full of yardwork and because I live in the midwest the air is full of corn dust, basically making it allergy season 2.0. At least in winter I can breathe and all the bugs are back in hell where they belong. Granted, snow sucks and having to shovel it is a pain in the ass, and having to drive around in slush and ice is a problem, but at least the city is usually pretty fast at getting the roads salted.
To flip the question on its head, what season do you hate the most?