Have you ever had a ridiculous crush that's made you act foolishly? That person infatuated or inspired unreasonable passion in you, causing you to become infatuated.
Infatuate comes from the Latin infatuat- meaning "made foolish." When you are head-over-heels for someone, you might have a tendency to act foolish. Most commonly, you'll see the word used in the term "to be infatuated with." When you are infatuated with someone, you're so enamored that you might behave in an irrational way. Stalkers tend to be infatuated with the subjects of their stalking.