It's different! Not being creative isn't the opposite of being cheery. The assumption is that the reader may not see any connection at all between happiness and creativity, and that the association might provide some insight. Though if you're like me and are only happy when you are able to create things, I can see why you would be irked.
I honestly can't tell if you're trying to troll me or not. Is there any adult alive who hasn't at one point realized that being depressed might--just MIGHT--impact one's ability to be creative?
