I think the answer to this question is that the most consistent way to make people happy is to have them partake in social group activities - going out drinking

I think the answer to this question is that the most consistent way to make people happy is to have them partake in social group activities - going out drinking, playing/watching team sports etc, watching movies - there's something hardwired into people's consciousness that when in groups, people tend to forget their own troubles and kind of adopt a common jolly mood, In contrast, almost all 'smart people' activities are solo activities or stuff with infrequent socialization - reading/writing, programming, playing/practicing instruments etc. Many of these activities are quite challenning as opposed to the former ones, so more likely to bring negative emotions to the forefront. 'Smart' people also tend to have elevated expectations of themselves, and they expect to either do better in general, or succeed in some niche that most people don't really concern themselves with - that leads to perpetual feelings of inadequacy. I'm not saying smart people are required to engage in these activities, I'm saying people should be more amenable to socializing and just chilling out together.