Should managers be giving more frequent performance appraisals? Do “customer feedback” questionnaires serve any useful purpose? The answers are not obvious. A feedback-free environment is not conducive to learning new skills, but then again, feedback itself can be confusing or demoralising.

I suffered from both too little and too much feedback in my last year of school. That was when I decided to stop going to piano lessons, having been coasting lazily at a mediocre level for years. My piano teacher, who had maintained a tactful silence, wistfully remarked that I had a beautiful touch on the keyboard – better than any of her hard-working, virtuosic prodigies. I was not impressed. Had she said that five years earlier, I might have worked harder. (Or so I told myself.)

It was also the year that I decided to spend less time with my A-level Further Maths exercises and more time with my girlfriend. I judged that my modest mathematical skills would not deliver a grade I needed to get into university, which would have to come from some other subject. Getting a C was no more useful than getting an E. So I stopped working, duly got the E, and did indeed get into university by other means.