The Bible says " do unto others as you would have done unto yourself..." Whether you are religious or not, I think it rings true as a great virtue to follow.
Consider seriously, what is the most precious trait of humanity, one that should be more evident in all of us?
Compassion. From that follows sympathy. It's seriously underrated, I think. It's so difficult to imagine yourself in someone else's shoes, but if you could just try to do that, so many issues would be solved before they become major issues.
The capacity to reason. It is from this that we can discern and change the world around us.
I am with Cameron and have to say compassion. Without it I think we just become barbarians.