Really? That many people hate this movie? And The Ref and Bad Santa are put out there as better alternatives? Thats cold... and sad.
The slapstick is there for the kids, that's your LCD humor right there. The rest of the movie is brilliant and it's the only Vacation sequel that stays true to the concept of the original film (flawed real world dad tries to make family gathering perfect, plan fails on an epic scale to the point that it becomes surreal, crazy idea ends up saving the day and the family, realizing that things never to work manage to cobble together something happy. It sounds dumb, but recall that Caddyshack is about a bunch of rich people that play golf until some asshole shows up, challenges them to tournament and Bill Murray blows everything up and Animal House is about a group of college kids that like to drink a lot.)
What's funny, for one there's the chemistry between Chevy Chase and Randy Quaid, Quaid is a scene stealer but it's the great back and forth between the two that makes the movie. On that note, you're severely underselling Chevy Chase here, he's at the top of his game and his comedic timing on every line is perfect. The rant he gives towards the end of the movie about his boss where he's just pacing around throwing a tantrum is hilarious for no reason other than the way he sells it, it's over the top but we're also watching a grown man throw a tantrum.
The other highpoints are Mae Questal (the part where she's asked to say grace and starts reciting the pledge of allegience is still one of the funniest parts of the movie) and every single line out of William Hickey's mouth is hilarious. Honestly I don't get how you don't find it funny, or how anyone would find Bad Santa funnier when literally the entire joke behind Bad Santa is that he's a drunk asshole that swears a lot dressed as santa claus, maybe if christmas vacation had more buttfucking jokes you'd find it funnier but I really have no idea.
