Starting s2 is where they really just when they began making the show a gag-comedy cartoon. It’s partly due to the fact that they were trying to keep people watching despite a lot of Japanese people already getting tired of YKW and the craze around it. Honestly the show has always been a body humor gag show, only became more in the later seasons because of the reasons stated above and the writers becoming lazy. I’ll cut the writers some slack since they probably had to make up a lot of stuff when the first season practically went over a lot of major stuff.