I know! This headline sounds like hyperbole. But I've been driving around this earth for 15 years and no one ever told me about this one key feature of the car interface. And I bet, nine out of ten of you haven't noticed this little cue either.

Here, take a look at this. It's just the dashboard of a car, in this case a Volvo. It's hiding an important bit of information.

Imagine that you rented this car for a big road trip to kick off the summer. And you're pulling into a gas station to fill up for the first time.

What side of the car should you fill up on—driver side or passenger side?

There's no standard answer. Some cars have the gas on one side; some cars have it on the other. So you either stick your head out the window and try to see, or you guess.


But that's only because no one had pointed out this arrow, right next to the little pump. Yup, that thing tells you what side the gas cap is on.


No, really: It's that basic. You will never again in your life not know the correct gas station procedure.

All these years, and a few dozen rental cars, and not one time had anyone ever pointed this out to me. Nor had I ever really noticed that arrow on my own. Like, not once. And the arrow has been standard in new cars for a while now.

One explanation is that I'm not the most observant person. I'll grant you that. But in my defense, the dashboard tells you real-time things—speed, fuel level, temperature, RPMs—not things about the fundamental design of the car (except, perhaps a rough top-speed). So I'd also never ever really looked—like looked looked—at a car's dashboard for this kind of information. Designers have noted that this particular part of the car interface is not so good, too.


But there might be something more fundamental going on, too. This tip is one of these things that once you know it, you assume that you're the very last one to find out. And no one likes to be the last to find out anything. So no one wants to spread the word for fear of having everyone be like, "Well, duh. It's an arrow pointing to the gas cap side. Who didn't know that?"

The features of this knowledge are interesting: there's never any particular time or place to learn it, and yet you should know because it's useful, and yet many people don't because it's not totally essential living life.

Ever since Fusion's own Kashmir Hill told me about the arrow, I've spent weeks pondering how many other things like this exist out in the world. (Not least because it's part of journalists' mission to deliver useful information to people.) How many other things do I know that no one else does or that everyone else knows that I do not?


It reminded me of the time that Google's in-house anthropologist told me that 90 percent of people don't know how to search a document (or web page) using Ctrl+F. To me, this was obvious and not even worthy of comment. To others (90 percent of people), it was mind-blowing.

There must be a category for this kind of knowledge that converts from unknown to obvious the second you learn it. And it should our collective duty to get over ourselves and share it.