Developing through each subsequent stage of life grants us greater control over our happiness and well-being.

In Stage One, a person is wholly dependent on other people's actions and approval to be happy. This is a horrible strategy because other people are unpredictable and unreliable.

In Stage Two, one becomes reliant on oneself, but they're still reliant on external success to be happy — making money, accolades, victory, conquests, etc. These are more controllable than other people, but they are still mostly unpredictable in the long-run.

Stage Three relies on a handful of relationsh.i.p.s and endeavors that proved themselves resilient and worthwhile through Stage Two. These are more reliable. And finally, Stage Four requires we only hold on to what we've already accomplished as long as possible.

At each subsequent stage, happiness becomes based more on internal, controllable values and less on the externalities of the ever-changing outside world.