英语俗语:A Chip On Your Shoulder

 A person who has "a chip on his shoulder" is angry because of some thing that happened in the past. Example: "He lost his game this morning, and now he hasa chip on his shoulder." It is easy for a person to get in a fight when he hasa chip on his shoulder, because he is already angry about something else. Example: "Watch out for that guy, he's gota chip on his shoulder." To start a fight, men used to putchips of wood on theirshoulderand challenge others to "try to knock it off". Example: "What's bothering that guy?" Reply: "Nothing. He's just gota chip on the shoulder." Example: "Tom had a tough time growing up, so he's got a bit ofa chip on his shoulder." You can use the definite article ("the") which sounds more general ("a chip onthe shoulder"), but more often people use the personal pronoun ("his", "her", "their") to say that that specific person has "a chip onhis(her,their) shoulder."