A variety of reasons. I can't pinpoint just one.

Many things go through my mind when I cut. Sometimes, nothing goes through my mind at all. I guess, after ten years, it has become more of a habit than anything. One I realize is bad and dangerous but I can't stop anyway because it feels like it's an integral part of who I am as a person.

I self harm when I'm depressed. I self harm when I'm angry. I self harm when I'm happy. I self harm when I feel like I don't recognize who I am. I self harm to see if I can feel it because sometimes I feel as though I can't. And sometimes... I can't until I realize what I've done. Which could be two minutes later or two hours later.

I can't accurately answer this question except to say "because I have for so long that it's just hard to stop". Sometimes, I can't even recall why I began in the first place. Though that's no surprise since I can't recall that part of my life much at all.