This article about MetaFilter pointed me to this thread on MeFi about life changing moments. While I certainly don't think that a comment thread on a web site is a representative sample, it's interesting that so many of them are negative. And I found it particularly interesting how many of the "horrible thing that shaped my life" moments were things that I experienced, but thought little of.
I was left at the park by my parents when I was five, and had to walk home almost half a mile by myself. I corrected a teacher, and was punished for it. I lashed out at someone with a blow that, if it landed, might have done serious damage. All of those, though, were just experiences that happened to me, and the lessons I took from them were positive, because my parents had laid a strong foundation of love and support.
Christie and I were talking about this at lunch today, and we decided that it's typically not the big things that shape our lives. What sets the course of our lives is not a single bad day. In a functional family, it's the million hugs, the being told again and again, "I will always love you", and the thousands of family dinners that make sure that a bad day is just a bad day.
At least that's the idea. The truth is, I'm just making this up as I go along.