Well, there are three prominent ones; embarrassed of one, proud of another, and the third's almost unnoticeable.
The embarrassing one happened while I was on my first date with this girl. I was waiting for her mother to pick me up at the bowling alley where my parents were bowling, under the instructions to inform them when I was leaving. When she arrived, I was so eager to leave that when I sprinted back into the bowling alley, I ended up slipping on some sand, throwing me into a roll that scraped up my elbow. To this day, I look down on it and I smell her perfume.
The unnoticeable one happened when my family went out to California for Thanksgiving and my mother's 40th birthday. My cousins, brother & I went to a park and played a little baseball. I was pitching to my high-school-varsity-playing cousin, when he cracks a line drive that goes whizzing by my head. I threw the next pitch, I hear the crack of the bat, and then I'm being picked up off of the ground, spewing blood from my broken nose, having no idea where my shattered sunglasses landed. The ironic thing is that prior to that pitch, in response to the ball whizzing by my head, I said, "I would hate to get hit by one of those." Several reconstructive plastic surgeries later, you can barely see it.
While that one is unnoticeable, my proudest is one that can't be seen. Back in 2005, I found myself in the hospital, being diagnosed with ALL. To make administering the chemo easier, the doctors installed a Groshong port into my chest. Unfortunately, it would seem that it would cause more problems than it would fix, so in December of that year, I was in the ICU, being told, "We need to take that out. Don't worry, it'll be a quick, 5 minute procedure." 30 excruciating minutes later, it finally came out, leaving me with a marble-sized hole in my chest. When I thought of the kinds of scars I'd get in the military, I never thought of anything like that.