I'm very keen on the Pareto principle - or the 80/20 rule. The basic premise being 20% of our actions will result in 80% of returns/reactions, and the other 80% of our actions or efforts provides a mere 20%. If you are able to determine what that 20% is, giving the 80% returns and you can simplify, avoid or automate the other 80% (ever wondered why 80% of employees in a company are essentially useless? 20% of the people generate more than 80% of the revenue in any company or organisation, it's unexplained in maths, yet seen in any sample you care to take ...
Great explanation of the Pareto Principle. It's close to a natural law in certain situations. The most amazing thing is imagine refining that 20% into a further 20% year after year. Retirement would be nonsense because you could be so insanely productive working one week's worth a year and be better off than most people.