scintillating - Describing someone or something that is exceptionally witty and entertaining, and is intellectually or emotinally stimulating.

Her scintillating conversation captivated those she talked to at the dinner party, leaving them laughing and enjoying themseles.
simmer - To heat a liquid, usually a stew or soup, just below the boiling point, allowing it to cook slowly; or to stay in a slow, controlled state of progress or tension, often before a larger event or change occurs.

He was simmering with anger, but he kept it inside and didn't say out loud what he was thinking and feeling.