Not sure how much I buy this. I had a similar situation to the OP in high school - a friend and mentor passed away and in the wake of his life I felt the need to Find My Purpose and conquer the world. While I realize with almost a decade under my belt that ForrestN has point - any individual mark tends to blur and disappear, I would still argue that during the days where I am fighting for something, those are the days where I feel good and alive. The days where I let ambivalence win are a waste.

I will say, the biggest difference in how I view the mark I want to make is that my scope has widened. Creating a product that changes the world, spending time with family, helping pass laws that make life Better according to my admittedly limited worldview all work.