He has the ace of hearts and the jack of diamonds, or maybe the other way around. This reasoning applies to limit poker as well, in a limited way. Okay, so maybe I'm not that good at reading hands after all. That's why I needed to find another way to get a jump on things. Everyone constantly reads people.
Kids do it, grown-ups do it, heck, even dogs do it.
We can't help it. The ability to read others is hardwired into us. Like when you're a week late paying rent, and your landlord cheerfully asks if you got that new job yet. Or when a cab driver asks you about the names of side streets. That's a setup for a takedown.