Whenever I think about past decisions that turned out to be poor choices, or the events of my past that have scarred me in some way, my tendency is to wish I could change the course of events. I think to myself that I would have done things differently, made different choices, followed a different path, and I would somehow be better off today. It's often difficult for me to view those experiences except in a negative light.
The thing is, everyone has those experiences that may have been the result of trauma, poor choices, or just plain unlucky coincidence. Every individual is the sum of all of their experiences, good and bad. I seem to have no trouble embracing the past of other people, and I can be boundlessly empathetic toward others. When it comes to my own past, though, now that's when I tend to be judgmental.
What I am trying to learn to apply to my own life now is to be as forgiving to myself as I tend to be toward others. Because it's not just me that I hurt when I am hard on myself. I am also not giving other people enough credit when I assume they don't accept me as the sum of my experiences the way I accept them. I like who I am today, even though I am far from perfect. And ya know what? Those imperfections in my friends are what endear them to me the most. I have to hope it's a mutual arrangement. :)