The students rarely get punished for groping, flipping skirts, and undressing women (it's not always Machiko). What will these boys turn into when they get older?
Worse still when you realize that one of the major complaints about the show were that students were emulating the kids in real life.
One episode has the class crash-land on an island, where they meet a stranded war veteran. Most of there interactions are Played for Laughs, but this guy has just been surviving on his own, meaning that he probably lost all his comrades, all while burdened with the thought that a traumatizing war was still going on for years.
Several episodes have characters being chased by large carnivorous animals. It's a good thing they were never caught by these things or it would have been messy.
You would think she would stop wearing skirts after the twentieth time they are flicked up.
Not only that, but if she has to stand up in front of a crowd (school play, PTA meeting, fashion show, etc.), Kenta will make sure she's naked in front of as many people as possible. You'd think she would stop getting up on stage anywhere.
Also, every episode deals with the faculty and students traveling to exotic locations, getting involved in weird mysteries, or getting involved in grand schemes. One has to wonder when they found the time to actually teach/receive an education.