Levi never showed his emotions, he always kept them in check. You'd never seen him smile or be happy, he'd get angry several times but nothing big, and he especially never got upset or cried. Not even when his teammates were killed by the Female Titan.

You were strolling around the Survey Corps Headquarters, and as you were passing Levi's room a loud crash startled you. Worried for the Captain, you rush in without knocking to see his room a mess, and a pained expression on his face.