I have seen ample happy dumb people and I am a very smart sad fellow

I wish I could be happy. Fake it to make it right?

I don't agree with this. I see happiness as a state of mind that we each choose - or not. That choice seems to have less to do with intelligence, and more to do with self awareness.

People can decide be happy in the most dire of situations. Many of the survivor stories from WW2 concentration camps attest to this sort of mindset.

I believe I am reasonably intelligent and though my life includes some struggles I would have to say I am basically happy. I enjoy my work and my time with my family and I enjoy my leisure activities: reading (SciFi and fantasy), anime and video games.

I could say it is easily explainable - the more intelligent you are, the broader/wider your "eyesight" and understending is, hence greater your wishes and desires, thus much more difficult to satisfy.