What's the value of being selfish or obstinate?

If I had to sit down and make a list of the biggest changes between age 25 and age 34, I think I'd only be 3-4 items into the list before I arrived at "Meeting more selfish people, daily." Now, there are a lot of arguments you can make before we even talk about being selfish -- for example, the nine years between me turning 25 and me turning 34 also had…