Other mistake: After his wife has a party at their house, Thorton Melon (Dangerfield) decides to have a swim in his pool. The camera shows Melon as he is about to dive into the pool from the edge. The camera cuts away and a much "thinner" Melon is seen doing a flip into the water. Watch carefully as the "thinner" man makes his dive. You can clearly see his hairpiece fly off the top of his head.
Thornton Melon: Listen, Sherlock. While you were tucked away up here working on your ethics, I was out there busting my hump in the real world. And the reason guys like you got a place to teach is 'cause guys like me donate buildings.
Thornton Melon: Please, try to understand. I don't have the background for this. I mean, the high school I went to, they asked a kid to prove the law of gravity, he threw the teacher out the window.
Thornton Melon: When's our first class?
Jason Melon: Uh, we got Economics tomorrow at 11 o'clock.
Thornton Melon: 11 o'clock? No good. I got a massage 11 o'clock. Tell 'em to make it 2 o'clock.
Jason Melon: No, dad. Uh, you don't get it. They're not gonna re-schedule the classes around your massage.
Thornton Melon: All right, 11 o'clock, but I'm gonna talk to that Dean. I mean, these classes could be a real inconvenience.