Thanks for the compliment and insightful reply!

I agree that selfishness isn't necessarily a bad thing. The way I phrased it in this post mostly betrays an unconscious influence of our current culture (which sees being selfish as a negative thing), I think. I try to be very aware of such biases, but you can't catch them all I guess. :-)

Agreeing to disagree is definitely a very strong foundation for friendship. I couldn't be friends with someone who doesn't respect my right to a different opinion. This doesn't mean however that friends shouldn't speak up against each other if they feel the other is crossing the line. It's a bit of a fine line, that surprisingly enough works very naturally and effortlessly in a healthy friendship.