I received my nickname from a famous musician. He called me the "Rockin' Dr." Back then, I was repairing and rebuilding a lot of instruments, and he was impressed with my work. I was the "guitar doctor," since I fixed sick instruments.
I don't have a real doctorate, but the humorous nickname stuck.
Been thinking on this one for a while now. And it's the opposite of selfishness.
And there are many options like generosity, altruism, kindness...
If someone can't put themselves in the skin of the others I'm afraid I won't be able to make friends with them.
Tough to narrow it down to a single one, but one I think a lot of which isn't mentioned often is consideration of others. It doesn't mean you always agree with another person, but you do take the time to consider the other person's point of view. As a whole society would probably be better off if people with differing opinions and thoughts actually listened to each other and considered what the other person was saying.
With that being said, a healthy dose of skepticism is important to have because sometimes people just spew utter bullshit.