Do not be too moral. You may cheat yourself out of much life so. Aim above morality. Be not simply good; be good for something.

Henry David Thoreau

My peers, lately, have found companionship through means of intoxication – it makes them sociable. I, however, cannot force myself to use drugs to cheat on my loneliness – it is all that I have – and when the drugs and alcohol dissipate, will be all that my peers have as well.

Franz Kafka

It is the nature of ambition to make men liars and cheats, to hide the truth in their breasts, and show, like jugglers, another thing in their mouths, to cut all friendships and enmities to the measure of their own interest, and to make a good countenance without the help of good will.

Sallust