It's when your boss yells at you, or your professor makes you feel stupid in class, or you have big fight with a friend and you just can't stop replaying the scene in your head for days, sometimes for weeks on end.
比如你的老板冲你发脾气了， 或是教授在课上让你感到愚蠢， 或是你和好朋友吵架了， 然后你不断的在脑海里 回放当时的情况，好几天， 甚至好几个礼拜都不停。