Diana

Diana is one of Main Character's best friends from college and first seen in Chapter 1. She is bookish and conservative mainly because it is what is expected of her, especially by her fiancé. Attending cotillion classes has made her well-versed in polite society and etiquette;

Spoiler

however, when she drinks more than two shots of tequila, she turns into “Diana the Destroyer” and becomes a metaphorical wrecking ball, eventually dissolving into a blubbering mess.

Diana has multiple insecurities, including never finding someone as good as Skip, disappointing her parents, and not being smart enough.