Most shameful? Letting people "get to me" easily when I was
  young. Easily goaded into fights or outbursts. I learned
  self-control but not through them. Biofeedback. Breathing. I
  would've needed that training _anyway_ because I had anxiety
  issues generally speaking, but a few of those outbursts were the
  moments I knew better and failed. Did the failure make me try
  harder to succeed? I don't think so. But they were tests. Some I
  succeeded in, some I failed at. I don't buy the argument of
  "toughing up" people. It just turns people into "me-too"
  assholes and I think I successfully evaded that mostly. I feel
  bad for those who got caught in the trap though. == I knew a guy
  once that was raised with a mother who believed in "toughening
  him up". I knew him when we were in our 20s and he was proud of
  how his mom raised him. All he knew I suppose. He had a dog.
  German Shepherd. He used to punch the dog in the face, sideways.
  He believed it was toughening his dog up. We didn't stay friends
  for long after that. His justification didn't resonate with me
  and it seemed abusive.and I started avoiding him when he'd come
  by to hang out. I told him off once about it but he didn't
  understand, but at least he stopped coming by after that. ==
  When someone was abused and says, "and look at me, I turned out
  fine!", I really look at them and I can see where they didn't.
  Not much can be done except try to prevent it from happening
  elsewhere if possible.