How does this cope with your loneliness? you know you don't want these people as friends. YOu plan to not connect with them going forward and furthermore have good reason not to want to have any part o your ex best friend's life.

While I can understand your apologizing to the coworker being a decent thing to do, I'm not sure what it does for your loneliness. Seems more like you feel compelled to have some kind of closure to these relationships.

As for the book return, I'm not sure I'd call it a kindness as much as an obligated gesture. When you borrow something it's not kind to return the item, it's just the right thing to do. Again though this seems more like a way to bring closure to that relationship also

So I am curious how you tie this into coping with your loneliness. I'm not being snarky I'm being honest about my curiousity.