Very true. I've never worked with kids, but after having kids myself and seeing this "chromosomal slot machine" pull in action, it's so apparent that a lot of personality is baked in. I used to be quite the behaviorist/blank-slatist too.

On the note of research selection bias, how about the realization that most research is done on college students who are trying to get class credit, and that most of the research work is also being done by students? And that it's almost never going to be replicated? I think the general public has this idea that most science is being done by a bunch of specialized men/women in labcoats with decades of experience, not hungover 20-somethings talking to hungover 20-somethings. In reality, that's probably 99% of it.