Katsuki is just around, honestly. For someone so loud, he happens to walk around unnoticed and hear so many damn conversations. How people don't notice that he's there is questionable. Sometimes he JUST SO HAPPENS to sit down with people talking behind him. Or walking through an area minding his own business when he walks into people talking about theirs.

His hands are always occupied with food though. Even in his own canon So what he really wants is just a quite place to eat his damn food.