Opportunity
When I was young, I was always in the current temporal event - without looking back and puzzling ahead. It was important to feel that there was an opportunity to get exactly what one wanted here and now. Now, through the distance of time, everything seems silly, a period of wasted time and missed opportunities... Yes, you can't bring back your youth to eradicate foolishness from your biography, but you can reduce it now, just to push back old age.
