This explains the complicated game called Life in layman terms.
First 15 years of life is a tutorial that you cannot skip.
There are many cutscenes in life that you cannot skip.
Every task costs a bit of willpower. It can only be restored by sleeping or relaxing but fades throughout the day. If you don't have enough willpower to spend, you cannot perform tasks such as working out or studying.
http://oliveremberton.com/2014/life-is-a-game-this-is-your-strategy-guide/