In February I had an x-ray and learned that for three weeks I’d been walking around on a fractured toe. Specifically, a “linear lucency … consistent with a nondisplaced fracture.” I’m still reminded of this every time I bump it or move it the wrong way.

For a long time I didn’t notice anything wrong. I mean, obviously I knew my foot hurt. I was limping. But it took me over two weeks of limping to notice my foot had hurt long enough and badly enough to justify calling a doctor.

Drive a car long enough, and something will probably go wrong. Maybe you hear a squealing noise, not very loud at first. Without really thinking about it you drive a little bit slower. Maybe the brakes are a bit soft, and you instinctively brake a little sooner to compensate. Gradually the noise grows. Gradually you drive a little more gently, and a little more. And one day you notice, hey, you’re driving at ten miles per hour and braking half a block away from the stop sign and your car still sounds like it’s rehearsing Tosca.

We do this all the time. We thump squealing refrigerators and dishwashers and clothes dryers into silence. We put up with TV aerials that must be adjusted and readjusted with microscopic precision to pick up signals. We live with watches that stop randomly and work with computers that crash and tolerate small appliances if they start to smell funny.

You can get used to all kinds of things. You can be used to a thing for a long time, until one day it hits you that you’re too used to it, and you’ve let it go way the hell past the point that it ought to be tolerable. I was amazed, and a little alarmed, to discover I could do this with my body.

Maybe the real lesson here is that life never ceases to provide us with new things to feel stupid about. Which in some ways is better than not feeling stupid. If we never felt stupid, would we notice when we had something new to learn?