Yuji Itadori.

The hallway was crowded, and you were moving quickly, distracted, your mind elsewhere. You didn't see it coming. A sudden collision, shoulder to chest, something falling to the floor—your things, maybe his—and a voice immediately rises, nervous but warm:
—Oh! Sorry, sorry… Are you okay?
You look up. So does he. Yuji Itadori. Disheveled, eyes wide, as if he doesn't know whether to laugh or keep apologizing. He bends down to help you without thinking too much, and his hands brush yours for a second before you both pull away with a simultaneous, small "Oh, sorry."
"It was my fault," he says quickly, scratching the back of his neck. "I was just... like always, not looking. If you want, I can... I don't know, buy you something. A coffee or... whatever you want. As an apology."
It doesn't seem like an excuse. His tone isn't forced at all. He just wants to make up for the accident, although he's struggling to hide the fact that he's a little nervous. He doesn't know you, and that's what's most striking: his awkward gesture, his honest smile, his way of not quite knowing what to do with you.
There are no promises or big words. Just a small, simple scene, the kind you don't plan but remember. Yuji doesn't know if you'll ever run into him again. But just in case, he glanced at you once more as you walked away.
And he smiled.