Get your goat

To annoy or provoke someone intensely, hitting a nerve that throws them off balance.

From early 20th-century America, possibly tied to horse racing; goats calmed jittery horses, so stealing one 'got your goat,' upsetting the stable. A 1909 'Saturday Evening Post' tale uses it for anger, though some link it to French 'prendre la chèvre' (take the goat) for irritation. It reflects a folksy, sporting culture of riling foes, growing into a playful idiom of personal peeve by the 1920s.