Vanity of the world

Whoever does not see the vanity of the world is truly vain himself.

But then, who does not see it, apart from young people who are wholly engrossed in noise, diversion, and thoughts of the future?

But take away their diversion, and you will see them shrivel up with ennui.

Then they feel their nothingness without understanding it, for it is to be truly miserable to be unbearably overcome by sadness as soon as one is reduced to reflecting upon oneself without any form of diversion.

Blaise Pascal — Pensees, III,70

Vanity

 That something as obvious as the vanity of the world should be so little known and that people should find it strange and surprising to be told that it is foolish to seek honors, that is astounding 

Blaise Pascal — Pensees III,50