I'm not so sure myself. It seems to me like "theory revision" is fun. However, I suppose it depends on the precise sort of theory revision we're talking about. When I'm revising my theories because I'm wrong/losing, it's a bit more negatively charged of a state than just idly speculating. However, that mood doesn't necessarily last long, and is quickly replaced by the pleasure of an "aha".

A long time ago, my wife and I learned to refer to these situations as "growth opportunities" -- said with an ironic look and a bit of a groan -- but viewing them as such definitely improved our moods in dealing with them.

Thus, I find it difficult to believe in a hardwired causal connection from revision->sadness, even though it's easy for me to believe in a connection going the other direction.

Personally, I think the "Lisa Simpson Happiness Theory" (negative correlation between happiness and intelligence) arises from the mistaken tendency of intelligent people to assume that their "shoulds" exist in the "territory" (and not just in their own map), because they can come up with better arguments for their shoulds than for those of others. Intelligence is at least moderately correlated with this phenomenon, and this phenomenon is then highly correlated with people not wanting to be around you, which in turn is at least moderately correlated with phenomena such as "not having a life" and being unhappy. ;-)