A boy bullied me for almost two years in school. Then one year, unexpectedly, he gave me a birthday card. It just said, "Sorry I was a jerk." After that, he mostly left me alone.
I'm 35 now and still have that card in an old box. We never became friends, and his apology didn't magically erase everything. But it was the first time someone who hurt me admitted it without being forced. I don't know why I kept it, but every time I move houses, that stupid card comes with me.