"80% of the wealth and income was produced by 20% of the population (aka: 80% of the results come from 20% of the effort and time)": Pareto's Law / Pareto Distribution / 80/20 Rule
"Perfection is not when there is no more to add, but no more to take away": Antoine de Saint-Exupery
"It is vain to do with more what can be done with less": William of Occam
