Nathan: Many JWs I knew in my long-ago youth would have said the purpose in life was to "be happy." I still think that is right
Me too. I think that people want to be happy above all else. The things we do and pursue are based on happiness at some level. I think it's very helpful for any individual to take stock of his/her life and figure out what would make them happy, then plan accordingly.
If I'm only here for a short time and then I am gone, I'd like to have lived a life where I was happy as often as I was able to be. That is the essence of the concept of enjoying what you have, while you have it. One of the more insidious outcomes of religious belief is that people will live a life of suffering and deprivation because they believe that life will really begin after they die. If they're wrong, the collective wasted talent over the course of human existence is staggering.