That is, when you value things that are based on things outside your control e.g. social validation, financial success, you will struggle to be happy.
When you value things that are intrinsic e.g. integrity, contribution, creativity, you will have a much better shot at staying happy.
The problem with 'intellectuals' is that they are more often pulled into the rat race where you are chasing extrinsic things. Also, they often value 'intelligence' itself, which makes you feel bad when you realize that the world is filled with smarter people. Also, intelligence deteriorates as you age.