I wouldn’t mind being over-happy. I don’t know what over-happy would feel like and I certainly wouldn’t feel happy to be not over-happy. I’ve seen people who seem over-happy but that’s about overdoing the appearance of happiness, not an abundance of happiness.
Happiness is a bit of a sticky wicket though. We seem to be always seeking it and almost never achieving it. I’ve read a lot of the happiness studies and many of them would seem to indicate that we know very little about how to be happy. Am I happy at the moment? Nope. Not even close. And even farther away from over-happy. I try to imagine what OVER-happiness would look like and I can’t even get a sense of it. Maybe it’s a cascading series of happy events? A ride down the hill of good fortune with so much speed it turns into an avalanche? I guess I wouldn’t want to be in an avalanche, even if it was made of happiness.