I'm not sure how to start this and not get lost in too much explaining and details. OK, so the shortest version possible, hopefully not too simplified.
Everyone has some soft spots. Some people have less, some people have more. For me, one of the biggest ones is self-dignity and how others perceive me. I know I should not care but I do. The other big one is "personal failures" or what I see as a personal failure, even if others might call them re-evaluation of my objectives or whatever. I have lots of those. I tend to not finishing things I start. I get easily excited for something, immerse in it, then something happens or changes, I lose focus, interest, abandon it and run away. Or hide it somewhere where nobody can find it (and see my failure). The less people knows about them the better. But some of them are... quite known.
Like the case with my Ph.D. I went through two years during which I lost illusions, found a steady full-time job, got another focus and completely lost any motivation in pursuing an academic career. Which of course clashed with the internal rules of the university resolving in an ending of my studies. It wasn't sudden, I knew it was coming, did nothing to prevent it, because I accepted it but still it hurt inside. It was an end of another era, one could say 22-year long era of my continuous studies, and it wasn't exactly as glorious as I would wish, or expected a few years ago. But it happened. I moved on, didn't lose the friends and still see them, even if sparsely.
Today it was used against me in a Facebook Wall conversation. I know, how pathetic! But I was called on "barely getting through two semesters of Ph.D." and some other stuff. And it stung. I thought I had got over it but it spoiled most of my day and I spent it thinking up millions of great and rightful (and some a bit nasty ) retorts just to defend my honour and good name. Even if I lost any respect I might have had for that person and I could rationally argue with myself that they are not worth any effort (and I haven't replied in there anyway), it still got me pretty low, and opened some laboriously closed issues about self-valuation.
So I was jabbed into a wound that would have needed some time to heal properly even without that. And I spent the day discovering I still don't know how to cope with these. :-( Even if I don't care what that person is thinking of me, what are OTHERS thinking? Do they see me the same way, as pathetic and loser? Do they agree with that statement? I see it as a public humiliation and since on the internet you never know how many people are watching, how to deal with that? But in general, how to deal with stabs in your soft spot?