People cut because it can make them feel better.
Ive been cutting for about two years on and off and the reason I do is that I have so mucs emotional pain all the time that I can't deal with but when I cut, it's physical pain I feel and it distracts me from my other feelings, if that makes sense.
No, it is not good to cut yourself, but sometimes it just seems like something you have to do. And a lot of people who cut end up getting addicted.
I have depression and have been abused pretty badly in the past so I guess that sort of brought it on.
I wish I didn't do it, but it makes me feel better.