Many have heard of the 80/20 rule.  

This is a derivation of the Pareto principle - a square root law which applies to nearly everything related to human creative output: if you have 100 people doing work, ten will be responsible for half of the productivity.

This seems to be true for wealth (i.e. in a group of 1,000, about 32 will obtain half of the total money), athletic performance (i.e. in an NBA with 500 players, about 22 will score half the overall points), and intellectual output (i.e. in a university with 250 professors, about 16 will create half of that school's published material).

This is a fascinating insight.  

A question: could this also apply human happiness?

Might a small proportion of your activities produce the vast majority of your overall happiness?

Creating those moments when you feel peaceful, true enjoyment, a sense of flow?

If so, it's wise to understand what that 20% is, and try to rearrange your life to maximize for those experiences.