chip on one's shoulder, to have a

*chip on one's shoulder

Fig. a bad attitude that tends to get someone easily upset. (*Typically: get ~; have ~; give one ~.) Why did you get so angry at the slightest criticism? You seem to have a chip on your shoulder.
See also: chip, on, shoulder
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

chip on one's shoulder

A belligerent attitude or grievance, as in Mary is easily offended; she always has a chip on her shoulder. This term actually was defined in a newspaper article ( Long Island Telegraph, May 20, 1830): "When two churlish boys were determined to fight, a chip would be placed on the shoulder of one and the other demanded to knock it off at his peril." [Early 1800s]
See also: chip, on, shoulder
The American Heritage® Dictionary of Idioms by Christine Ammer.

chip on (one's) shoulder

A habitually hostile or combative attitude.
See also: chip, on, shoulder
American Heritage® Dictionary of the English Language, Fifth Edition.

chip on one's shoulder, to have a

To be quarrelsome; to carry a grievance. This turn of phrase originated in nineteenth-century America, when, according to an article in Harper’s magazine (1857), placing a chip on a man’s shoulder and daring someone to knock it off was a provocation to fight.
See also: chip, have, on
The Dictionary of Clichés by Christine Ammer
See also:
  • have a thin skin
  • not lay a finger on (someone or something)
  • not lay a finger on someone
  • not give two hoots about (someone or something)
  • not care/give a damn
  • not give a damn
  • drop everything
  • lay a finger on somebody