How could we apply the 18-40-60 rule to our social skills?

This rule means when we are 18 years old, we worry about what everybody is thinking of us. When we are 40, we don’t give a darn what everybody is thinking of us. And when we are 60, we’ve come to realize nobody’s been thinking of us all this time.

This is a pretty neat rule. So how could we apply this rule to our social skills journey?