"Et tu Brute, then fall Caesar". Perhaps the most famous words in English literature speak of a betrayal of a friend. Julius Caesar is saying that if even his close friend Brutus is stabbing him, then he has no hope. Our friends are the ones that we expect will stand by us through thick and thin. When we're facing hardships, we ask that they be "our bridge over troubled waters". If we can't count on our friends to pull us through, then who can we count on?