I said before in my review of Hotel Transylvania that I don't hate Adam Sandler, and it's really mostly true. It's not that I find Adam Sandler openly offensive so much as it is that I've just lost respect for him.
I first started to lose respect for him at the point where I realized that all of his movies were basically exactly the same, just with window dressing changed. Happy Gilmore, Billy Madison, 50 First Dates, Anger Management, Click... every single one of them follows the same plot: Adam Sandler is a selfish, stupid asshole who, with the help of a wacky sidekick, learns how to be slightly less insufferable and gets the girl. Only the details change.
Then I lost more respect when it occurred to me that even in the Sandler movies I enjoyed, Sandler himself was never a really good or even memorable part of the movie. The best part of each movie is something entirely unrelated to him. In Happy Gilmore it's the foul-mouthed Bob Barker screaming about how much Gilmore sucks at golf. In Billy Madison it's Chris Farley as the psychotic bus driver (followed closely by Steve Buscemi as the insane would-be serial killer).
And then he made Grown Ups and I kinda started wishing he'd get hit by a bus.
Okay, so maybe I was wrong about not really hating Adam Sandler. But I did also realize that Adam Sandler is basically the perfect mirror image opposite version of Robin Williams. No, really:
Robin Williams was an oddball nutcase who was difficult to relate to but in a way that's fun and, if you think about it, kinda genius.
Adam Sandler is an everyman that everyone can relate to, but only by virtue of being blandly generic and dumb enough to appeal to the lowest common denominator.
Robin Williams was so hilarious and unpredictable that he stole every scene he was ever in.
Adam Sandler is trite and unfunny and constantly outshone by his funnier co-stars.
When Robin Williams realized his tendency to steal the show he attempted to rein it in, going so far as to demand to have his name removed from the advertising for Disney's Aladdin. (Disney refused his demand, however, and he eventually backed down.)
Adam Sandler always has to be the star of the show.