I realized that I was in love with my best friend when I slapped them in the face
What was your reason for slapping your best friend in the face?
Because he always acted like an asshole to me and I wanted him to finally understand what it feels like to be slapped by a girl.
It isn't fun to be mistreated, however, slapping your best friend isn't called for under any circumstances. Talk through your issues with your friend and work things out instead.
So what? When you're in love you do everything you want.
Not really sure what being in love with has to do with slapping someone. However, slapping someone, especially your best friend just seems wrong unless it was some sort of inside joke. Hopefully your friend's face was ok after this.