I'll go first. Mine is that I can't stand the Deadpool movies. They are self aware and self referential to an obnoxious degree. It's like being continually reminded that I am in a movie. I swear the success of that movie has directly lead to every blockbuster having to have a joke every 30 seconds
Cillian Murphy was good, the historical figures were well represented if you know a bit about the history of quantum mechanics, and the overall movie was a disappointment compared to the hype at the time, but it will be forgotten. That doesn't mean it SUCKED though.
Sucking is subjective. The same film can not suck for you and suck for BoastfulDaedra. That's what an unpopular opinion is about - if you disagree with them, you should upvote them!