Toss me in with the “there isn’t one,” lot. You do or you don’t do, and the brain keeps thinking until it doesn’t. But I guess if I had to slap one on there, it’d be one of the most basic-level things that most all successful forms of life achieve: to propogate.

You exist because for hundreads of thousands of years things fucked, fucked, and fucked some more, until you got fucked into existance. Now go, continue the cycle, the fuckening must go on.