When you really starting digging into your past, you’re bound to run into situations where people weren’t so nice to you. Of course you may have not been so nice to people sometimes, either, but that’s another issue. Sometimes these events, even where someone did something really awful, are essential to your story. They may bring on an important point that you want to make, but then you stop and think, “Uh oh, what if so-and-so buys my book and reads what I said about him/her?”
I was a little nervous about that, too, believe me. I didn’t want to offend anyone. But some things just have to be told. One way to protect yourself is by changing the name(s) of the protagonist(s). You want to be careful that you don’t set yourself up to be sued. Get advice from a lawyer if you’re not sure.
I found that when I went through my book the second and third time that I simply took some things that people had done to me because they weren’t ALL that important, even though I had thought so at the time. I just couldn’t see the point of hurting these people for no reason.
One rule of thumb I’ve found helpful is to sit down and sincerely forgive, to the best of your ability, anyone who has hurt you. Then if you feel you need to write about them, you’ll be able to do it in a more balanced, less edgy way, and still get your point across. I’ve found this to be very good for my own peace of mind, too, since it has encouraged me to look at both sides of a situation instead of just my own point of view.