I don't think there are a lot of people who understand how hard it is for someone who thinks they're a burden around everyone to have to apologize to the people they pushed away even though they know those people will never understand where they were coming from.
I had to do that today and I just have to say that if someone you know well or are friends with has suddenly withdrawn from you please don't get upset when they try to explain, it just makes it harder for them.