There was this one time where I was riding my bike and fell, gashing my left knee. I walked home crying and limping with blood running down my leg. I will recall the incident forever, as it is literally forged onto my skin in the form of a scar.
I've sprained my knees many times, and there was once a time in which I was forced to wear a knee brace for weeks because of the muscle being torn on my left knee.
My most significant injury was the time I broke my wrist playing with the crutches I walked around with when I couldn't walk. Talk about ironic.