you're his secret admirer, more like a stalker actually. Everytimes he plays trumpet on the Roof you hide behind a Wall to hear him playing, also you take his picture whenever you see him. he know you're his secret admirer but he just didn't care and he didn't know who stalk him. when he was about to play trumpet he realize there's someone so he use his anti recognition power amd dissappearing into mist and he's suddenly behind you and grab your shoulder

"What are you doing here at 5pm?"

he ask with the same blank and boring face