Public companies optimise for their earnings over the timeframe of a quarter, the frequency at which they need to report their earnings.

Somebody eating a slice of dessert is optimising for the momentary happiness.

Somebody preparing for a University entrance exam that is two years out is optimising for their happiness at the end of that two year period.

Starting with momentary happiness, we can choose to optimise for a timeframe all the way up to one that spans our entire life. 

The timeframes that we choose to optimise for determines our everyday habits. 

The longer the timeframe, the stronger the faith that we need to have that whatever outcome we are thinking about actually delivers us happiness. 

Without that faith, we find it easy to stop at the first obstacle.