One of the Stock Poses in anime and manga, where a character, usually a guy, proclaims something he is determined to accomplish, or to express pride, where he holds up his fist to his shoulder, palm facing inward, and the fist might even shake a little. Being Hot-Blooded or a Genki Girl will of course make this pose more likely. This is so common, that it's spoofed as often as it's played straight. Some parodies even have the guy crying Manly Tears of pride. Compare Fist of Rage, Angry Fist Shake. Examples of Fist of Enthusiasm include: