Well, the best way for me to reconcile these types of thoughts is to take the attitude that I should do my best to enjoy my life while I'm here, that's it. If it pleases me to make long term goals that will better my enjoyment of my time on earth then I will do so. But I do it with the understanding that I and my accomplishments will not survive the ages.

Just enjoy the time you have here on this planet as best as you can.