Copy Cat
Is there anything more frustrating than when someone else steals your thunder? Everyone has that thing about them that is “their” thing. So when someone comes along and tries to take that thing away from you it can feel very frustrating.
Having someone steal your joke and say it louder can make you feel lots of different things. And the way that this guy managed to encapsulate what the other guy was saying by copying what he said but in caps lock, is a comedic genius.