Don't shit in the hand that slaps you
To have respect for those who control your manners, paycheck, and just plain the way you act.
Such as.... 1) don't shit in the hand that slaps you as in your parents because they slap you with that hand by controlling your existence. 2) don't shit in the hand that slaps you as in your boss or supervisor because they control raises at review time and promotional futures. 3) don't shit in the hand that slaps you if of your wife or girlfriend because, well, we all know what she does with that hand don't we?