One of my best friends used to cut herself a while ago. It was a really tough time for her because she told my friends and I that she had family problems and told us that none of us could understand her situtation, so the only thing to do was to cut herself. Being the loving friends that we are, we got her some help and she's doing fine right now.
There's a couple people I know who actually cut because they are really depressed and think that's the only way for them to go. And then there's some really stupid people who cut themselves for the fun of it. I've never tried cutting. It just makes me sick to my stomach to let a razor rip my skin open and seeing all that blood come out... o_o