When I first saw it, it really made me laugh. Every time I've seen it it's made me laugh actually. The humor has a lot of variety, and while at times it may go a little blue, it still has a pervasive wit to the jokes that 100 better reviewed movies don't. But more than that, the characters feel like people you'd meet in the real world, and moreover, remind you of people you actually know. Every one of the characters have quite a few personality quirks, and while they certainly aren't portraid subtly, they definitely make every character even more believable. The best choice I think they made was basing the lion's share of the humor in dialogue. Not only is the dialogue funny, because there are plenty of movies with funny dialogue, it's true to life to an extent you could scarcely find a few examples of in film. That's just my opinion though and I realize everyone's tastes are different so I look forward to hearing your reasons for liking or disliking Grown Ups.