i have a new term.
passive idiocy: this behavior is occurs when someone is upset at you because you have kindly and politely put them in their place and tries to exert empty authority and agression upon you at a later time and fails horribly because they are too timid to make even a passing comment in your presence and you find out about their meek attempt of self consolation as they make those comments they should have said to you to someone else and a fourth party inadvertently hears it and reports it back to you. (yeah it's kind of circuituous, i'll have to make a diagram of it. pictures tell a thousand words. and bad karma is a bitch).
species likely to be found exhibiting this behavior: homo insapiens insapiens rolandus crackus moribundus.