What gives your life special meaning and purpose? Do you think it's important to leave a lasting mark on the world? If so, what form do you think this will take?
Everything you do has an effect. This is part of the basic law of karma. When you do good things the effects will be good; when you do bad things the effects will be bad. All of these effects (linkages in chains of cause and effect) spread out, like ripples on a pond, and they reflect back upon you.
This is a very simplistic description of course, of an extremely complex process but one of the things that someone might aspire to is to leave no footprints. Not to have good effects or bad effects, but to have no effect at all.