Well, I went from "Hip Hop/Rap is awesome!" as a kid, to "Hip Hop/Rap is garbage" as a teenager, to "Eh, there's some good songs here and there" now.
Similarly, in middle school, I went through an "anime sucks" phase, probably burned by Inuyasha at the time and how it just kept going. When I entered high school I started getting curious about it, and then watched Death Note, and it reinvigorated my interest in anime. I still like Death Note, too, although in High school I loved Elfen Lied, but now I really dislike it. Having rewatched it a while back and read the manga, that's... not a good show... like... at all, and even the manga has some problems that got to me.
Other than those, I was kind of a pseudonihilist as a teen, and always tried to act cynical to look smart and be funny, because Yahtzee was doing it. I say "tried" because deep down I knew I didn't believe that stuff, I just really wanted to. I would also try very hard to be "shocking" in school or online, because I was an attention hungry prick.
Nowadays I'm a very optimistic person, maybe aggressively so, because now I can't stand cynicism or nihilism. It creates an uncomfortable atmosphere for me and it's not fun being around people who are negative all the time. I just want people to be cool and loosen up a bit.