Tim Bray writes about his impressions of a gathering of very experienced techies:

As I looked at all these very senior engineers’ faces, I was struck by a particular look in their eyes. I don’t seem to have a good vocabulary to describe it, but "stillness" and "coolness" come to mind. It wasn’t subtle. They are the eyes, I think, of people who listen intensely.

This struck a chord in me, and made me think back on engineers I have worked with, the exceptional, the average, and the mediocre. I thought about their eyes. Interesting.