I was discussing an error I had made in a calculus problem becaues I tried to integrate a function of x with respect to z. I pointed out I made the error largely because my calculus skills are rusty, and I was just remembering a password ("velocity is the integral of acceleration!") and pushing on a magic button (INTEGRATE!) without remembering exactly what I was doing (calculating the area under the curve of a function of x, which doesn't make when you try to do it by adding up tiny pieces of z). At the end of my post-mortem, I linked the article and said it talked about some of the issues I was trying to articulate.