Original Sin

We are sinful not merely because we have eaten of the Tree of Knowledge, but also because we have not eaten of the Tree of Life.
(Franz Kafka)

Plasticity is a double-edged sword

Plasticity is a double-edged sword : the more flexible an organism is the greater the variety of maladaptive as well as adaptive, behaviors it can develop ; the more teachable it is, the more fully it can profit from the experiences of its ancestors and associates and the more it risks being exploited by its ancestors and associates.
(Donald Symons)

Life is pain...

Life is pain, Highness. Anyone who says differently is selling something.
(William Goldman, "The Princess Bride")

Life is like...

Life is like an onion: you peel it off one layer at a time, and sometimes you weep.
(Carl Sandburg)