I try very hard to not overthink movies. I also try not to have any feelings, pro or con, about a movie I'm about to watch. But, regardless of how much effort you put into it, there are times you are going to buy into the hype, get turned off or have some other feelings about a movie based on the advertising or something you heard/read somewhere.
I can think of several movies where I had a notion that it was going to be good, only to have my hopes dashed at the performance. Ang Lee does The Hulk??? That should be awesome! EEEEEERRRRRRRNT! Wrong answer. What I am having a hard time thinking of are movies I thought were going to suck and wound up being quite good.