I disagree with all this. Intelligent people are unhappy because they spend more time analysing life than engaging in life.

Life is meant to be engaged with. But often smart people stand on the sidelines analysing it from afar.

Reading endless books about the world but never actually travelling to see it for yourself.

Reading endless historical books but never trying to become part of history yourself.

There are highly intelligent people out there who are smart enough to know how to be happy.