Why do we sometimes fight harder for others than we do for ourselves, even when it leads to personal pain?

Do women who want a man to approach her, believe that they should smile at the man? Well, I feel that way, in any event.
What are some signs that you're genuinely starting to move on from someone, even if it doesn't feel like it?
Why might someone feel embarrassed after sharing something personal in therapy, and how do therapists typically respond to that?