Motivation: What drives me

I was reading an exercise mag and the subject of motivation came up. They commented that an altruistic motive is more important than a personal motivation. The example of the altruistic motivation was "I want to get healthy for my kids". This brings up an interesting point on perspective. The reason why you want to stay alive for "your kids" is because you want to see them grow up. It is a selfish reason, it is a personal reason and it goes back to the issue of things being relative. What might be a good motivator for you would suck for me, and viceversa.
I know that my motivation right now is simple: I'm tired of double digit jeans. I want to wear perfect size 8 jeans. Sounds like a selfish, stupid reason. But for me, it is a matter of logic. That is the most common size of jean in the store, and usually, the difference between brands is not that great on a size 8. For some reason the difference seems a lot bigger the larger the size.
So I will keep my selfish, "personal" reasons. You keep yours. Keep trying.