I don't know your secret. But I feel like what L said about what you didn't learn in childhood plus childhood curiosity makes a lot of sense.
Like, I know this is a really mild example, but if a child never learned that stealing is wrong, and they wanted something at the store that their parent wouldn't buy, it wouldn't be surprising if the child stole the item (or if they took it from a friend's house, say). As compared to an adult who *knows* stealing is wrong shoplifting or stealing from a friend. I think it's much easier to be forgiving and understanding of the child.
I understand your judging yourself more harshly than you might other people--I do the same. And it's something I'm working on in therapy. I like the idea of shining the light in the darkness so that the thoughts lose power over you. My T has tried to do some things like that with me. And also talked about positive things that have ultimately come out of the bad things, even if it's just that I better understand and can have greater compassion for others. Or in one case, something bad that I did that ultimately improved my marriage (even though it threatened it at the time).
And I agree that there's a difference between doing a bad thing and being a bad person. I'm not religious, but it makes me think of the line of "hate the sin, but love the sinner." We all do bad things, but it doesn't make us bad people, especially if we learn from them. I hope you and L and keep talking about it and that she can help you with it.