That first ding is always enough to give you heart palpitations. After a while, though, the marks start to give the git some character. Shows it's lived a little. I have a big wear spot on the back of my Melody Maker where it rubbed up against all the belt buckles I wore when on the road. When I first realized there was some damage there, I moved the buckle to the side when playing, but over the years it grew anyway and I decided to leave it.
Here's someone with a guitar that has a bit of wear and tear on it:
That's Frank Zappa with a Stratocaster Jimi Hendrix burned. He replaced the damaged electronics and other hardware so that it was playable again, but left the body the way it was. Effing cool axe, that.