For some reason, this made me think of a very silly quote from Hudson Hawk:

"And happiness comes from the achievement of goals. It's just that when you've made your first billion by the age of nineteen, it's hard to keep coming up with new ones. But now, finally, I've got myself a new goal... World domination!"

I think in the end, it really is a balance - of being in the now and still looking out for the future, while reflecting at times on the past. All things in moderation and all that. No matter what though, time passes much too fast.