The stock market doesn't "beat" anyone. People beat themselves. Price is the only thing that matters. Adapt to it or suffer. Being a good saver doesn’t automatically make you a good investor.
The discipline which is most important in investing is not accounting or economics, but psychology. 99% of all statistics only tell us 49% of the story 100% of the time.A retirement plan without a written plan isn't much of a plan. A tax ignorant financial strategy will lead to ignorant results. Making money is half the battle; keeping it is the other half. People who invest without an adequate margin of safety are clinically insane.
The only investors who shouldn't diversify are those who are right 100% of the time. Taxes will be permanently raised to pay for temporary reductions.
Target-date retirement funds are a good idea for everyone except you and everybody that you know.
If people and markets were not irrational, great investment opportunities would never exist. Everyone has the brain power to make money in stocks. Not everyone has the stomach. There are two kinds of traders: Those who are humble and those who are going to be humbled.
Your investment portfolio should not be a source of anxiety.