I don't know if I'm embarrassed to like or obsessed with any of the choices below, but:
I adore Transformers, but somehow I think people only hate that movie because it's a fad to hate anything by Michael Bay. Hence, I don't think anyone should be embarrassed for enjoying it, as it was excellent for a movie of its genre.
Anyway, I also enjoy Batman & Robin for its almost limitless degree of imagination, even though it was hardly Batman-like. I just loved the way it didn't take itself seriously. Although it pissed all over the Burton/Schumacher Batman franchise, people tend to underestimate how creative this movie actually is on its own.
With that said, I don't think I should be ashamed to admit I enjoyed both Fantastic Four films, but mostly because it was just light-hearted entertainment compared to Spider-Man and Batman Begins.
When I was young, I used to watch the Ernest movies. And that fact alone makes me embarrassed.
Let's see, what else?
I also love Sky Captain and the World of Tomorrow, another creative movie that most people don't seem to appreciate.
Innerspace is another movie. Like the vast majority of Joe Dante's movies, it's corny as hell, but it has a distinct display of invention. Same with Matinee and, to a lesser extent, Small Soldiers.
But I don't know if I'm embarrassed to be obsessed with them. Hell, I don't even know if I'm that obsessed with them. Transformers was one of those few movies that I can still watch over and over, for some reason.
EDIT: Why is this topic in the Fluff Zone? I think it more than deserves to be in the Arts & Entertainment section. Just a suggestion.