80/20 Rule

Idea

The 80/20 rule was an observation made by Italian economist Vilfredo Pareto in 1896. Pareto observed that 80% of the land in Italy was owned by 20% of the population.
majority of particular outcomes in systems are often caused by a disproportionately low portion of the possible causes
ratio doesn't have to be 20% causing 80% outcomes
little hinge that swings big doors

As a parent 80% of your kid's memory of you will depend on 20% of the time you spend time with them (the best and worst)
As an investor 20% of your individual stocks will give you 80% of increase in your returns
In career, 80% of perception about you will be based on 10% of the hours you work — decisions you take, presenting to senior management (even in that 1 or 2 particular ideas)

Know that you can make smart bets / decisions that can change your life in a positive way ⇒ look for high-leverage opportunities (high upside with low downside) and do the best you can. These opportunities will always look risky
Solve one macro problem that once solved other problems go away
Life is not "win all / lose all", but "win a lot / lose less"
80% of your happiness will come from 20% of your activities ⇒ jogging, spending time reading, spending time with your loved ones etc. Identify and try to do them frequently
Turn your mind from hours worked (esp in corporate jobs). Never discuss hours worked. Always, always talk about the outcomes you produced. This means you, in turn, shouldn't bother about hours you work, focus on big ticket items, grab those opportunities, and do your best work.