Be More Chill is a coming-of-age story about a high school student named Jeremy Heere who takes a pill that gives him the ability to be more cool, confident, and popular. The novel follows Jeremy as he navigates the social hierarchy of his high school, makes new friends (and enemies), and tries to figure out what he wants in life.
The message of Be More Chill is that it's okay to be yourself. Jeremy starts off the novel trying to be someone he's not, and while that gets him some attention, it doesn't make him happy. It's only when he starts being himself again - warts and all - that he finds true happiness and acceptance.