Chip On Your Shoulder
Q.
This particular idiom refers to people who are perennially cranky, irritable, quick to go off. Why? Because they feel they have been ill-treated in the past.
Where does this phrase originate?
.
A.
Chips on shoulders stem from a call to fighting in the 19th Century US. A person who was in the mood for a fight would put a chip of wood on their shoulder. “Who has the guts to knock it off?”
A similarly fight-ready person (or a soon to be not so innocent bystander) would knock off the shoulder wood, and the mayhem would begin.
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