Do you think you find them or do you think you are just very well able at identifying them?
I have two friends going through divorces right now. In that process, they've both revealed that their STBX's "drink too much" and that they "have thought off and on that he might have a drinking problem." I've nodded my head and thought to myself "I could have told you that just based on how you've described his behavior and demeanor to me, from 4,000 miles away."
I like you run across them everywhere. But I believe it's the second -- that you can pick them out of a crowd pretty easily after having intimate experience of one. Even if they're sober you can pick them out.