The trouble is that we have a bad habit, encouraged by pedants and sophisticates, of considering happiness as something rather stupid. Only pain is intellectual, only evil interesting. This is the treason of the artist: a refusal to admit the banality of evil and the terrible boredom of pain.
Perhaps it's possible to write something that's all glib and happiness. I don't know yet if I can do it, but I think it can be done.