I was sitting at my favorite local waterfront “conference center” (aka marina pub) late last summer swapping solutions to the world’s problems and spinning boating yarns, truthful and not, with some friends.

Eventually the topic turned to the two inevitabilities of boating: seasickness and groundings, specifically debating their terms and euphemisms: Does one actually need to lose one’s cookies to be considered seasick or does mere nausea qualify? Is a grounding really a grounding if you aren’t actually stuck—hard aground—or does that most delicate of terms “touching bottom” fill the bill?

When the Buffalo wings arrived, the mal de mer debate understandably ceased, and we began swapping tales of going where the water wasn’t. Somewhere around the time the fritters showed up, someone offered this comment: “Did you ever notice that people go aground coming back in a lot more often than they do going out?” General derision soon morphed into a reluctant acceptance and then into an energetic embrace of this as everyone remembered how many more late-day mishaps they had endured than early ones. Various explanatory theories were proffered, including the influences of fatigue and alcohol, the diminution of natural light, and something about sunspots.

A few days later, in a more contemplative venue, I pondered this phenomenon—especially since it seemed to jibe with my experience. I did a little research and came across an article in The New York Times about something called “decision fatigue.” The article is long and quite involved but the topic is fascinating and worth looking into if you are regularly called upon to make multiple serial decisions, as is a captain. The upshot—and I’m really simplifying here—is, to quote the article, “You can’t make decision after decision without paying a biological price.” The article goes on to point out that decision fatigue is different from physical fatigue in that you’re not consciously aware of it. Furthermore, the more choices you’re called upon to make in a given day, the more likely you are to suffer from decision fatigue, the more serious it is likely to be, and the more likely you are to take shortcuts. Shortcuts manifest themselves in two ways: being reckless or doing nothing, neither of which work well on a boat when you’re trying to find your way back to port.

The study’s most important finding is that you can’t avoid decision fatigue, short of off-loading decisions to others—which of course is itself a decision. Indeed every decision counts. Whether you’re trying to figure out which lure to use or which swimming trunks to wear, you’ve only got so much mental energy.