One of my favorite attendings in residency used to quip: "Don't just do something, stand there!" This was said in the Emergency Department at UCLA, not exactly known as a place of passive observation in the face of chaos, but the underlying Hippocratic rationale was solid: unless your intervention is likely to help the patient, first do no harm.
Strangely, may physician-investors who take an oath not to harm their patients feel no such compulsion to avoid harming their portfolio.
I'm not talking about the financially literate doc who enjoys tinkering and running analysis because the activity brings them a sense of accomplishment. If you are going to pursue a hobby, by all means choose one with a tangible benefit like developing a competence in personal finance.
I'm referring to the folks who choose individual stocks the way professional athletes choose lucky underwear. By following their gut instead of creating and sticking to a solid investment policy statement, they all but ensure that there will never be any method to their madness.
They chase performance, buying the hot actively managed funds their colleagues discuss at the water cooler, without realizing that last year's darlings are likely to become this year's stinkers due to mean reversion.
Worst of all, they spend countless hours trying to find a short cut to wealth by attempting to time the market. We've all encountered an irritatingly aggressive driver who keeps dangerously weaving in and out of lanes every two minutes in an attempt to beat the freeway traffic jam, and a few of us even get to witness the satisfaction of seeing said driver pulled over to the side of the road exchanging insurance information with the unlucky driver she just rear-ended. Just as it's the patient driver who stays the course that arrives safely at their destination, so it is with the calm investor who avoids the common errors that we are predisposed to make.
There's something zen about passive index fund investing - what Jack Bogle has called "the majesty of simplicity" makes life easy without compromising long-term returns. You decide on the level of complexity you want for your asset allocation, invest accordingly, check perhaps once a year to rebalance your portfolio, and the rest of your time is free for the pursuits that bring you fulfillment alongside those people that give your life meaning.
It's a beautiful thing when a simple but rational solution to an ostensibly complex topic like investment strategy rewards the person who spends more time doing things that bring them pleasure out of proportion with those they love.