I find "What will your grandchildren think?" to be a decent heuristic. For example, I admire my grandparents a great deal for their community service. My grandmother is in poor health, but she still gets around for charity board meetings. In her prime she was a pillar of civil society in my home town. Thinking of what future generations will appreciate pushes us to think outside of ourselves.

I know less about my great-grandparents, but I admire them for emigrating to America and struggling to make a better life for their kids.

Granted, on the cosmic timeline their actions don't amount to too much (because nobody's do). But I definitely feel the impact of my great and great-great grandparent's decisions.