Hercule Satan: he is so fucking obnoxious he's not even comedy anymore, just a show of cringe. He shitted on all of DBZ gang's efforts and sacrifices to save the world from Cell and they thought it was a great idea to keep him around as Gohan's father-in-law. What a middle finger to all that Cell's Games arc drama. And his daughter was not the apple to fall far from the tree. In the beginning when she was stalking Gohan she was just as annoying. Imagine having a classmate always trying to stick up their nose in your business, checking where you live, where you head to after classes etc.
Bulma: they made her bearable towards the end, but I remember during Frieza arc she was so bitchy and selfish, I was wishing all the time somebody would kill her off and eventually bring her back alongside with everyone when summoning the dragon.
Chi Chi: they turned the brave little girl into a toxic helicopter mom. You can say all you want that she wants the best for her son, but that's not how this works in real life. If your parents force you to study and become a doctor when you're fucking 4 and cannot reason much, you usually grow up miserable and hating them. But I guess she was supposed to impersonate the classic Eastern Asian mother stereotype. Either this or Toriyama doesn't know how to write female characters much.
Gotenks: just a bratty snotty fusion of two bratty snotty kids. World's in danger and all they're worth is gags and quirks. At least Gohan had some real character development, from a crybaby to a brave and just teenager. Goten and Trunks are just some plot device who, after failing to add anything meaningful to the story, were not cared about enough to even have some aging process.
