This was definitely one of my numerous childhood memory movies from the 1980s along with "Back to the future", "The breakfast club", "Ferris bueler", "Caddyshack", The "Karate kid" films, and the "National Lampoon vacation" films. And many others.
"Back to School" and Rodney Dangerfield went together like cake and icing. The movie would obviously not been the same without him, it would've then been another quirky raunchy college comedy.
I liked Rodney's (Thorton Melon's) tough friend Lou (Burt Young, who also played a tough "you better not mess with me" character in "Rocky"). Lou didn't hesitate to take care of a bully picking fights in a bar. Even Thornton's son's friend Robert Downey Jr. cries to Lou during the fight "where you been Lou? I've been getting my a** kicked all over this bar!" Downey did toughen up some in later years, but not always in good ways.
Thornton's son Jason was played by Keith Gordon, another one-hit wonder actor that I never remembered from any other movies. Jason complains how he only got onto the diving team and the fraternity because Pops bought his way onto it all, which was true. Before that, he was no one special to anyone really and shared a little dorm room with his only friend Downy. Jason didn't make the team due to the coach (Emett Walsh) saying he wasn't that good. Rodney has Jason dive doing the "two and a half", which does flawlessly, causing the coach to reconsider his opinion. Thorton also reminds him about his legendary dive "the triple lindy", which the coach once saw not knowing it was Thorton.
Thornton was a man with money from owning his "Tall and fat" stores ("well, you're short and ugly" Thornton tells a wise** kid who points out that he's "Tall and fat"). Thornton really did buy a lot of Jason's newfound success, including hiring a work team to do his and Jason's homework, much to Jason's dispair and his dad then retorting "kids, they always wanta do it the hard way". Also a funny joke is that Thorton hires 'the' Kurt Vahnaghan himself to write his term paper on Kurt Vahnaghan, leading to another funny joke when Thornton's told by sultry teacher Sally Kellerman that "whoever wrote that paper doesn't know the first thing on Kurt Vahnaghan".
Thorton takes a "drinks for everybody" approach at the university, according to Roger Ebert. That he does. He buys everybody's schoolbooks who's present at the college store, he hires staff to do his and Jason's homework, he hires Oinga Boinga themselves to perform live at his frat house party (and pays the police to bring the beer, much to stuffy teacher Paxton Whithead's dismay), and he dedicates a wing at the college to himself while getting dirt thrown on Paxton with the ceremonial shovel.
Thorton paying Jason's way also gets attention of the obnoxious William Zabka character, he tells Jason at the swim meet "your father already bought your way onto the swim team, I'm sure he bought off the judges too". Zabka does not play the same kind of menacing bully in this movie that he played in "Karate kid" and "Just one of the guys". Here he plays more of a yuppie snob, and Jason is actually the one that punches him, and Zabka never even hits him back or comes back onto him later about it. It was kinda like the tables had turned here on Zabka.
I also like the classroom scenes and still find them funny. The late Sam Kinneson going "Ahhhhhhh!!!! Aaaaaahhhh!!!!". The sultry Kellerman (who Thorton very keenly starts dating) who reads a romantic poem with Thorton almost unknowingly standing up in class saying aloud " yes!! yes!!!" Then the stuffy Paxton Whithead's business class teaching how to build a business from the ground up and Thorton, who has a lot of hands on experience in the business world and is rich "Tall and fat" business owner himself, corrects Paxton making him look bad at every turn. Also is the "what's a widget?" line. Answer being "a fictional product, it doesn't matter". They should've waited another 20-30 years to mention that one in the world of the internet. No longer a fictional product and widgets do matter.