Immune to insecurities

I am dating someone who has loads of insecurities, body image issues, career dissatisfaction, etc. The insecurities are not to the point that they're annoying, they're just there and in ways in which this person readily accepts about themselves. The whole thing is actually pretty attractive to the sadist in me. But it has also gotten me thinking about what it means to be insecure. See, I don't think I've ever been insecure. I know it sounds absurd. It’s not like I think that I am the best at everything. I am well-aware of my many failings. I guess it’s just that they don’t bother me, and I certainly don’t identify with them in this bizarre, fixated way that I often see people do.

I was talking to my friend about this, because she often suggests that I am overly secure with myself. We had the following conversation:

M.E.: I think you're the one that's really made me realize that I am basically not insecure about anything

Friend: If anything you're oblivious

M.E.: Oblivious?

Friend: To others reactions or positions which in turn insulates you and makes you immune

Very insightful, I thought. I do seem to have the ability to be targetedly oblivious to things. I know in the abstract that there are people who hate or judge me, but I probably wouldn't be able to name specific people. Is this the origin of my confidence? Is it really because I don't care what people think, or that I think they're wrong, or maybe that I just am blind to others disapproval.