I see sports fanaticism as an extension, or an abstraction, of a hard-wired tribalism that I expect was a defining feature of social life for pre-modern humans

I see sports fanaticism as an extension, or an abstraction, of a hard-wired tribalism that I expect was a defining feature of social life for pre-modern humans and probably pretty useful in that environment. (In much the way allenp notes below.) I try to avoid loutish public expression of it as much as possible. But I still find myself impulsively taking sides in sports contests whether it's Packers vs. Bears on tv, or Android vs iPhone in my favorite online forum, with all the attendant assignments of good and evil. It's hard in my experience to avoid tribalism but easier to hide. I like people who take a side (well, my side, anyway) where it counts and I recognize that where it counts is a slippery matter. Being able to suppress the expression of gratuitous tribalism is, for me, one of the markers of a cultivated mind.