Keep Your Identity Small, by Paul Graham.
A friend of mine recommended this article, and I found it useful, so here’s to sharing.
I think what religion and politics have in common is that they become part of people’s identity, and people can never have a fruitful argument about something that’s part of their identity. By definition they’re partisan.
The most intriguing thing about this theory, if it’s right, is that it explains not merely which kinds of discussions to avoid, but how to have better ideas. If people can’t think clearly about anything that has become part of their identity, then all other things being equal, the best plan is to let as few things into your identity as possible. 
Most people reading this will already be fairly tolerant. But there is a step beyond thinking of yourself as x but tolerating y: not even to consider yourself an x. The more labels you have for yourself, the dumber they make you.
The wise friend who share Graham’s piece with me also has a website worthy of your attention: http://rbiser.com/