I can't think of any recent off the top of my head, but coming across a girl I liked in HS on Facebook reminded me of one from then.
We were in class in theater style seating. She was a few rows below me. Not thinking, I start pulling tiny pieces off the gum I am chewing & tossing them in her hair. I did this a few times. By the time my stupid ass realized that it was not paper (What I intended), it was too late.
She, obviously, hated me after that. Later that day, her big brother slammed me against a wall & threatened me.
So what do I do as an adult? I message her on Facebook, of course! Let's see if she even replies. I doubt she'll even remember me anyway.