Scar: When I was younger I walked into a lamp post, the electricity door thing had been crow barred open at the top and was left serrated. It made a massive slice right above my knee and for about 6 years I had a very obvious and large scar that everyone always pointed out and I'd then embarrassingly tell them a detailed story of how I got it
Geometry: I almost failed Geometry in high school. If my teacher hadn't taken pity on me and made my retake exam identical to the original exam, I would've been toast.