I accidentally hit my crush in his grind. and all he did was smile at me and walk away. why did he smile? usually people frown or yell. but smile?

i was in class standing in the middle of the room cuz we had free time and i was talking to a freiend. so im moveing my hands back and forword by the side of my body and my crush disides to walk by exactly wen my hand is going back. so i hit him in the grind. it fritend me cuz i didn't know he was there. but all he did was walk a little and smile back at me then went to talk to his friend. And I don't know his smile. it wasn't a smirk or anything it was a really sweat smile and no i wasn't a creepy smile where ( ooo she want's the D!!!) ( eye roll) Any ways it was like the smile you give some one when they just told you you love them or some thing.
I accidentally hit my crush in his grind. and all he did was smile at me and walk away. why did he smile? usually people frown or yell. but smile?
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