Favorites would have to be SpongeBob, Fairly Odd Parents, Gumball, Beyblade, Dragon Ball and Dragon Ball Z, G Gundam, Yu Yu Hakusho and some others Im probably forgetting
Most hated is a tricky one because I feel like most of the shows I "hated" back then were based off what youtubers said about them, which is why Im refraining from bringing up Teen Titans Go at all here. But there are two shows I didnt like growing up, one of them being Ninjago because I felt a show about ninjas was too westernized from the few glimpses of it I saw whenever my little brother would watch it. Another one is Dragon Ball Super (and this one is recent since it came out during my teen years), and I think this was the first time I had truly hated something and not because a youtuber told me it was bad. It wasn't an instant thing but it would grow as I watched through the show and got more annoyed at every terrible story decision, blatant attempt at nostalgia pandering, and dont even get me started on how flanderized Goku's character to the point of parody. Yes he's a dumbass! Yes he likes fighting and can be selfish because of it! But those werent the only traits Goku had as a characters and the writers for Super didnt seem to grasp that.
Just remembering this but I also didnt like the Garfield Show from CN after they started going super meta about the fact that it was a show. That would be fine if the show had started out 4th wall breaky but it didnt so that shift felt very jarring to me and turned me off it completely. It broke the illusion for me personally and from what I remember, the 4th wall jokes werent done in a cleaver way that would actually make it funny