I don't doubt your story, but your timeline is off. Arena was introduced with BC, which was Jan 2007 -- 6 years ago, not 9. It would have been impossible to buy arena points 9 years ago because they didn't exist.
That aside, I don't see that as selfishness, just introspection. If selfishness is doing something for your own benefit, then you did an unselfish thing. You made the lives of everyone around you better, and contributed more to your family and society. That isn't selfish!
The main point of my post was a reaction to the point I quoted. Based on that quote, it sounded like the OP was focusing on parts of self that may not result in happiness or becoming a better, positive person -- success and intelligence.
I know many people that are successful and intelligent, but aren't happy or positive -- at all.
That moment of selfishness, is what helped pull me out of whatever rut I was in. 8 years later, I have a black belt in one martial art, a blue in a second, and I'm offering nutritional tips to friends and family.
Happiness doesn't have to be volunteering at the soup kitchen every week, but the general "Don't be a dick to anyone" can really boost your mood. I'm not saying be a doormat, stand your ground, but don't be a dick about it either.