A wonderful post that I'm sure was very humbling to write. I've known many people who are very smart and can successfully solve difficult problems, but actually working with them is absolutely abysmal because of the very reason Boz describes. Empathy is such an important thing when working with others, and it's something I try to bring with me to every situation.
It's not always easy, of course, especially in those moments when you think you're correct and everyone should just suck it up and listen to you. It wouldn't be fair for me to claim that I have mastery over swallowing my pride and listening to others be wrong. However, it is something I work on every single day, because I want people to like me. No, not so I can stroke my withered ego, but so I can reach a level of harmony with others that ultimately creates a better work environment/relationship/friendship etc.
Kindness costs nothing, and many times it'll open up more opportunities for you than just being smart or possessing raw talent. People like being treated well, and it's easy to work with those that treat you kindly. I will prioritize that sort of harmony in my day to day life over surrounding myself with brilliant assholes.
This is not to say that intelligence or talent aren't important, but people that possess either (or both) would do well to not rest solely on those aspects of their personality. Intelligence has a nasty habit of evolving into arrogance, and it's at that point that even the most intelligent of people frequently turn into the dumbest people in the room.