NOT long ago, I bought a new Braun toaster because I was fed up with the way the old one left a golfer’s tan on one side of the bread and ignored the other side altogether. It is early days, but the new one appears to work much better.

Yet what is even more impressive than its ability to grill bread on both sides simultaneously is that it came with a 15-page manual telling me how to operate it.

Do not use unattended, it said. Only use in upright position. Do not place toaster in a heated oven. Do not use for other than its stated use.

The manufacturer’s fervour for instruction was impressive but was rather wasted on this simple machine. I have been operating toasters successfully for more than four decades and have never put one in the oven. I have found them all the same — they toast for a bit and then they give up.

User manuals have a point only for machines that behave in ways not obvious to the novice or that vary from one brand to another.

I’ve always thought that the machine most crying out for a manual was the human being.

There are some general operating principles, but each model is different in important ways. If you watch people making toast, you’ll find that one person cuts the bread so thick it gets stuck every time, while another always makes two slices but only ever eats one.

Until last week, I thought the idea of a human user’s manual was a jolly fantasy, but then I stumbled on a real example on LinkedIn: a guide to himself written by Aaron Hurst, the social entrepreneur.

"People are way more complicated than machines and it is about time we start helping our colleagues understand how we work," he explained.

The idea of a guide that sets out an individual manager’s style, preferences, likes and dislikes is so good it is extraordinary it has taken us a couple of thousand years to come up with it.

If only I had had a manual for the normally friendly boss who cut me dead in the lift one morning, I would have known he was merely hung over.

Instead, I concluded he was about to fire me.

Equally, it would have been good to have known that the manager who sought me out, asking me to tell him a difficult truth, really wanted an easy lie. I told him the truth; it was years before he spoke to me again.

More generally, the manual would reveal which bosses prefer phone to e-mail. Which are better approached in the mornings; which are better never approached at all. Which abhor sloppiness. Which are suffering mood swings as a result of marital meltdown. And so on.

Alas, Hurst’s user guide to himself didn’t quite live up to its billing. "I created (it) for my team to help understand my flavour of craziness," he writes, thus setting the self-knowledge bar rather low.

He then starts to explain what makes him tick: "I believe in giving people opportunities to grow, and pushing them beyond their comfort level."

The guide tells me two things: I don’t want to work for Hurst and such manuals are better written by a third party. The toaster doesn’t write its own; neither should the boss.

Hurst didn’t invent the manager’s manual — it was borrowed from a Bloomberg BusinessWeek blog, where a better blueprint was set out. It recommended a guide should include such invaluable pointers as: "I don’t give much positive feedback. If you don’t hear from me, I’m happy."

Alas, the blog met a hostile response. Most management thought is based on the sentimental idea that we can learn to change — to give great feedback, and so on — and so it was not deemed good for a boss to announce his shortcomings and expect underlings to work round them.

Yet in true life, people don’t change much; so if everybody knows what their boss’s little ways are, it is better all round.

Recently, I experienced the user manual concept working to great effect when I watched a seasoned chief executive address his top managers.

He leapt up on stage and declared that he was rotten at remembering names and so would be jolly grateful if anyone he spoke to reminded him who they were. This was a masterstroke: he was saved from having to gawp desperately at name tags; and his underlings were saved from paranoia when they found their boss didn’t know them from Adam.

You could say that a better answer was for him to get better at remembering names.

But if you know a decent way of doing that, I, for one, would really like to hear it.

©2012 The Financial Times Limited