cartoons I don't get 14

Punch October 6, 1925

Punch October 27, 1915

Adam, July 1973

It took a few tries for me to figure this one out. I know the idea is that you're hypnotized into forgetting you've taken the course and pay over and over again, I just think it should've been worded differently.
This Is It #22, mid 60s

The things people did when sex before marriage was the joke itself.
Good Humor, circa 1964

Why don't they have a doormat like everyone else?
Hello Buddies, June 1952

Hello Buddies, May 1955

Trump had this cartoon in his office when he was managing the Miss USA Pageant
side note: she has no belly-button
Laff, July 1952
Bill Wenzel

Punch October 27, 1915

Punch October 6, 1915

Playboy, January 1961

Pad June 1968

Nugget, February 1956