What does it mean when a person snaps?

5. intransitive verb. If someone snaps, or if something snaps inside them, they suddenly stop being calm and become very angry because the situation has become too tense or too difficult for them. He finally snapped when she prevented their children from visiting him one weekend.

What causes a person to snap?

“Why We Snap” outlines nine, but some of the most common ones are a life or death threat, threat to a loved one, threat to your home, or threat to your tribe. “Our brain is wired to constantly be on the lookout for threats,” Fields says. “In response to sudden danger, we react automatically; you can’t think about it.”