From time to time, we all make dumb mistakes—and it’s easy to feel terrible, and to ruminate about it. Right now I happen to be preoccupied with a silly mistake I made in ordering the wrong size of a product. I tell myself, nobody’s perfect, these things happen, it’s truly not a big deal, it could have been worse, and all those other reassuring statements—but still, it bothers me. It was just such a dumb mistake to make.

At such times, I find it helpful to remind myself of other very dumb mistakes that others have made—and not just one person acting alone, but entire teams of highly accomplished people.

The fact is, mistakes happen.

Consider the cup. Game of Thrones was an enormously successful television show on HBO that ran from 2011 to 2019. The show, based on a famously as-yet unfinished series of novels by George R. R. Martin, is high fantasy, set in a vaguely medieval world filled with castles and swords and dragons.

In episode four of its eighth and final season—and remember, this is the final season, so it’s not like this incident involved a bunch of newcomers who didn’t know how the system worked—a modern to-go coffee cup appeared on a massive table right in front of one of the main characters, Daenerys Targaryen. There it was, a to-go cup with a lid, a sleeve, it was unmistakable, it was visible for about two seconds. When the mistake was discovered, HBO quickly edited it out, but the oversight ignited thousands of conversations, especially on social media. People got such a kick out of jumping on the mistake!

Of course, I’m sure that for the people involved, it was awful. You tell yourself, “We’ve done this extraordinarily complex show year after year without a single mistake like this, and we mess up for two seconds, and no one will let us forget it.”

Well, mishaps sometimes make the best memories. Everyone loves the story of the coffee cup. (Which, for the record, wasn’t from Starbucks.)

A less whimsical and far more costly mistake was made by NASA.

In 1999, NASA lost its unmanned $125 million Mars Climate Orbiter, which was sent into space to study the weather on Mars.

What happened? What led to the loss of such a valuable piece of equipment?

It turns out that spacecraft engineers forgot to convert from feet to meters when exchanging vital data before the launch. The team that designed and built the spacecraft used inches, feet, and pounds, and the navigation team used the metric system. In such a complex and sophisticated operation, they made the dumbest mistake.

This resulted in a simple math error that caused the craft to burn up in Mars’s atmosphere.

I’m reminded of a quotation from Benjamin Franklin’s Poor Richard’s Almanack, which an old boss of mine used to repeat frequently. To understand this quotation, you have to know that “dear” is an old-fashioned word for “costly.” “Experience keeps a dear school, yet fools will learn in no other.”

The fact is, mistakes happen. Even a roomful of top Hollywood professionals can overlook a coffee cup, and even rocket scientists can make a simple math error. Nobody’s perfect.