Err, I would say For DIU is Crazy Noisy Bizzare Town (Cheery), that...Next one I can't even remember its name and is the only intro I ever skip for Jojo, which is depressing and kinda grundgy, and then the Third one which is cheery and Upbeat.

I always assumed it was because at Core Jojo is a very optimistic series. About people working together, the voice of love, and justice and all that good jazz.