My wife and I are watching Game of Thrones, for the same reason almost everyone else is watching: We've already invested seven seasons. We want to see how it all turns out.

This is a horrible rationale, of course, and not just because the eighth and final season is so horrible.  

If you don't watch Game of Thrones or don't care, I apologize. But 17.4 million Americans watched the premiere, which is slightly larger than my readership. So I'm willing to assume some overlap.

I'll try to put all of my objections into one sentence, and then move on. (I'm not alone; h/t to Elahe Izadi at The Washington Post. Oh, and "spoiler alert!") You can skip this and just go to the next paragraph if the show isn't your cup of tea: 

This season's epic battle scene was filmed with such poor lighting that I almost missed the pure tactical incompetence of the show's heroes, who sent their most elite cavalry force, the Dothraki, alone against an overwhelming army of undead warriors, presaging a string of errors so egregious that they sparked an entire genre of comprehensive online analyses by real-life professional military planners, which in turn prompted backlash (like, "nice job critiquing Game of Thrones, maybe now work on getting us out of Afghanistan, sir?"), foreshadowing the parade of missteps, plot holes, and character inconsistencies in the most recent episode, which will forever be symbolized by the fact that a misplaced and wildly anachronistic Starbucks cup somehow wound up on camera.

You get the point -- and if you don't, it's that throwing good time after bad, as many GOT viewers agree we're all doing according to an unscientific survey of Twitter posts and Reddit threads, is a really bad practice.

Among economists, it's called the sunk cost fallacy, otherwise known as "escalation of commitment: holding on too long to a strategy that was once successful."

That quote comes from Harvard Business Review. There are a lot of other places describing sunk costs, but I already have a subscription to HBR. (Ba-dum-dum.)

The sunk cost fallacy is also one of the most tempting traps in life and business.

It's why people who should never be lawyers go back for the second year of law school, why salespeople bang their heads against the wall with recalcitrant customers, and why companies push forth blithely with products that nobody really wants or needs.

And it's why I'll be watching again next Sunday. It all ends May 19.