Happy STS! What weird things are your OCs obsessed with? Does that obsession change or has your OC been a fan of this one thing their entire life?
That would depend on the definition of OC's to be honest.
All my Oz variants like chocolate, just like they do in canon. Glass is semi-obsessed with living his father down, and so is Wes.
Tip is... sort of obsessed with protecting those he cares about, those he loves. It's a bit of a character flaw, to be honest, and it's been taken advantage of a few times.
Talking of the Tipverse, Reuben Arc [who nobody's really met, and doesn't use that name] tends to mostly be obsessed with running his shop and staying out of the war. Because he's sensible.
Talking of the Strangers verse, Gem Escarii tends to be obsessed with causing trouble. [affectionate] He's a joker and can be a bit of an idiot, but he's also a really good person to have at your back.
Hope that was more or less what you meant!