Drop everything and run when you come across ...
Feelings of certainty. They invariably come just before big surprises.
People who claim certainty. It's the most potent way to trick someone.
Risk-free returns. You'll end up with return-free risk.
People who have predicted 564 of the last two market crashes. And there are a lot of them.
Adjusting your risk-tolerance when stocks are either crashing or surging. It's the easiest way to make a financial decision you'll regret.
Putting 30 years worth of savings into something you spent seven minutes researching. You have no right to complain about losing money in an investment you put no effort into understanding.
Extrapolating the recent past into the future. Things always change. If your forecast doesn't, you're doing it wrong.
People who aren't willing to change their minds. Including yourself. Especially yourself.
Feeling smarter after the market goes up. You had nothing to do with it.
Explanations of what were likely random events. This means almost every market move that takes place in time periods less than one year.
Having political feelings within ten miles of your investment decisions. This is a common way smart people make dumb decisions with money.
Spending more time arguing why other investors are wrong than trying to figure out what you're doing wrong.
Spending the majority of your time in a job you hate in order to make enough money to spend part of your time in a life you don't hate.
Precision. Finance just doesn't work that way.
Impatience. It's the fastest way to disappointment.
Investments you can't explain to a third grader. If you can't, you probably have no idea what you're getting into.
Assuming your past investing behavior isn't indicative of your future behavior. It's the best guide you have.
Assuming that the random life experiences you've had provide a complete view of the world. Everyone has their own version of history and it's a tiny reflection of reality.
Reliance on pensions, inheritances, Social Security, or the decisions of anyone other than yourself to make it through retirement. Few third parties care about your wellbeing decades from now.
Six-figure student loans before you're old enough to drink. This is starting out life with your hands tied behind your back.
Assuming investors who wear suits are smarter than you. Being a smart investor has little to do with education or job title and everything to do with behavioral traits.
Assuming intelligence in one field translates to being a smart investor. I doubt there's any correlation.
Assuming that bad investments you made were the result of bad luck and good investments you made were all skill.
Measuring investment fees in basis points instead of dollars. An advisor saying, "My fee is 100 basis points" sounds so much better than, "This will cost you $35,000 per year."
Feeling entitled to investment returns, a decent job, or predictability.
Trading on margin. Most people can't handle market volatility without leverage.
Trading, in general. You're fighting randomness and computers that can solve a trillion problems before you can blink.
Worrying about things you can't control. Like what the Fed will do next, what the market will do next month, or whether earnings will beat expectations.
Avoid those, and most everything else should fall into place.
Check back every Tuesday and Friday for Morgan Housel's columns on finance and economics.
Contact Morgan Housel at firstname.lastname@example.org. The Motley Fool has a disclosure policy.