Chip on his Shoulder
指某人因過去的不快而心懷怨恨，容易動怒或挑釁。
形容人因舊怨而態度敵對。
英文釋義
Angry today about something that occured in the past.
例句
He still has a chip on his shoulder about losing the championship last year.
典故來源
源于19世紀美國，男孩將木屑放在肩上挑釁他人，若被撞掉則引發爭斗。