What does “set someone off” mean in English?

When something sets you off, it suddenly makes you angry. In the clip, a podcaster talks about her short temper and says small noises “set her off” — they are the trigger for her anger. The phrase paints a small picture: like lighting a match, one small thing, a noise or a comment, can start a big reaction.

You can be “set off” by many things: loud sounds, rude comments, or small annoyances. It is related to “having a short temper” — getting angry quickly and easily. In the clip: “Like little noises or loud sounds, they really set me off and irritate me.” Another useful phrase from the same clip is “get on my nerves,” which means to slowly annoy someone, different from the sudden spark of “set off.”