One afternoon, when I was a kid - no younger than eight, but no older than twelve - I spent a very happy afternoon cutting myself with a pocket knife. It wasn't a very big knife. In fact, it was tiny and was attached to a keyring. It was, however, extremely sharp. I sat down one Saturday afternoon in front of a movie on General George Armstrong Custer. Whilst watching the film (which was good), I slowly and carefully cut nicks across the top of my foot and on my wrist. They weren't deep nicks, just deep enough to bleed a little and then dry up. It didn't hurt. Nobody saw me.
Most of those wounds quickly healed, but I still carry some scars from that afternoon - a couple of almost invisible white marks on my left wrist, just above my watch.
I don't know why I did it, and I didn't do it again.
Every scar tells a story: there's the snick on my lip caused by my careless teenage hand wielding a blunt razor; the white line on the top of my head from where my three year old younger brother threw a plastic bus at me when I was watching TV; the lump on my forehead from when my elder brother smacked my head against a garage door; the jagged line along my right thumb where I tried to catch a mug just at the instant it smashed on the side of the hot-water machine and its smaller, more hooked reflection on the palm of my left hand; the small purple mark on my right shin, the remains of a pressure sore from some ill-fitting ski boots; the faint mark over my ribs caused by the studs from someone's rugby boots as I drove them into the ground on a pitch just off the M69 near Coventry when I was 17... I'm 32 years old, and I've got the scars to prove it. If you were selling me on Ebay, you'd probably have to say that I was slightly worn.
I've got some other scars too, scars of unknown provenance. Perhaps they're the most interesting of all.