When we were courting, Dawn made a comment about programmers that struck with me.
Dawn had had very little social interaction with programmers before she met me. Then she met a bunch. One day, we were talking, hand in hand, and this happened:
Dawn: Your friends are nice... [wait for it] Dawn: But... Dawn: They have really strong opinions. Dawn: About *everything*.
I realized that oh how true it was. Of me especially.
That was reinforced later. We were at a party. It was 1999. A veterinarian buttonholed me and explained in considerable detail how straightforward and easy solving the Y2K problem 
was. I nodded politely as he pontificated, while thinking "You *badword*, you have *no idea* how complicated that job is."
Then I was struck by two back-to-back epiphanies: 1. I, as a programmer, do this sort of thing – explain to other people how simple their job is – *all the time*, and 2. I've met a lot of veterinarians since meeting Dawn, and this is the first one that's exhibited this kind of ignorant arrogance.
Made me think. Intellectual humility: it's what [should be] for breakfast.