why I'll never be happy?

This picture sums it all: no brain no pain.
We hear as a clichet: "Ignorance is bliss", and the truth is that dumber people tend to be happier.
Well I think I am a very rationalist and intelligent person so because ignorance is bliss, that's why smart people are so depressed and gloomy whereas happy people are so goofy and annoyingly cheerful.
But as Ernest Hemingway used to say:

And well I don't care what you think, 'cause as long as it's about me, the best of us can't find happiness in misery!