If you don’t think that the little wheel on your mouse that lets you scroll up and down is important, just try working on a program without it.
It turns out to be rather difficult
My mouse scroll wheel failed today. So I changed the batteries in the mouse, then I moved the radio receiver closer to the mouse. Neither of these worked.
So I just blew hard on the wheel. Result. I’m reminded of the fun I’ve spent debugging over the last couple of days. And I’m also reminded of a saying that seems to work when programming, mending mice or even (and this is a reference to fun had years ago) fixing water leaks.
The fault is never where you think it is.