Comment by Oui_wissal on Flashlight - Chapter 31

After rereading this, I understood something like yujin trying to give Aaron a popsicle when they were younger because he was his fan but Aaron made fun of yujin or smth in some way, and it hurt little yujin's pride and feelings and he sets this whole we're from different worlds, and we aren't fit fir each other, 

remembering that memory when he looked at his reflection with Aaron realization hit him and he wanted to leave, it's my guess of what's happening probably.