This thread has helped me.
This week I have been feeling sad that things didn't work out with someone at my work.
It's a painful situation... especially when it's a person you like.
I must say, I've been learning to try to keep roles clear. It's helpful if people you have influence over don't take you into their confidence too much. It's hard to recover from a loss of trust.
I doubt my own behavior. Was I good leader? Did I make requirements clear? How did the person respond?
In the end, it's just a job. There's always another one.