"becoming rationalist"- there's an 'ism' there that raises my hackles a little. But there was one experience not long ago that piqued my interest in cognitive bias: I quipped to a friend, "When I do it, it's processing. When you do it, it's drama."

He called that attribution bias, and now I've started a collection of biases that I think I understand in my gut. Most of them seem highly mental and theoretical, but that's mostly because I have so few points of contact with other people.