Just assume each one of your friends is a raving moron until you observe evidence that contradicts that fact. Half jokingly, my alibi for getting out of FB was

Just assume each one of your friends is a raving moron until you observe evidence that contradicts that fact. Half jokingly, my alibi for getting out of FB was "On moral grounds, I cannot offer my support to a company that was started through borderline fraud and is known to change its privacy-policies/terms-of-use without notice".