Flips one lid is an informal slang term used to describe a person's extreme reaction or outburst in response to a situation. Some antonyms for this phrase could include staying calm, collected, or composed, handling a situation with grace, or maintaining a level-headed approach. Other antonyms could include being indifferent, apathetic, or disinterested, indicating a lack of emotional investment or investment in the outcome. These contrasting antonyms demonstrate how individuals can choose to respond to situations with different levels of emotional intensity, depending on their personal tendencies, values, and emotional intelligence.