There comes a time in your life when it strikes you that you are never going to be a ballerina/footballer. Usually, when you are about nine. It is a complex feeling, in which the predominant emotion, disappointment, conjoins with a small but definite sense of relief. It is as if you can tangibly feel yourself growing up. If you were a tree, you would have a new growth ring. They recur, these moments of self-realisation, as you get older, prompted perhaps by biology or the things you see and hear. If you don't have them you're either lunatic, or famous.

When you're young you think it would be great to be important, to make a difference. But the more I see of public life, the more I think it must suck. On Thursday there was a new biopic of Margaret Thatcher. It didn't attack her policies or her public persona. It went straight into the bedroom and the kitchen. It made her out to be – let's be frank – a right cow, cold to her daughter and husband.

Those who served around her in government were also ripe for mocking or vilification, whichever served the story better. I'm not making a party political point but a point about public achievement. People make you pay for it, and go on paying for it. Strangers will make cruel jokes about your private life after you're dead. Why stick your head above the parapet at all?

I am not calling for a return to deference in public life. It's too late; it would be like calling to the sea to be still, and besides, deference sounds too much like forelock tugging or a lack of essential public scrutiny. No, I am just setting out the consolations of underachievement. They are many, but they are usually silently celebrated. Why? They should be worth vocalising, now that everybody wants "to be famous", or its middle-class equivalent, "to change the world". Living and loving in dignified anonymity should be honoured too. To any right-minded person there must be nothing worse than being "important".

The unbearable anxiety of power was illustrated very movingly this week at English National Opera, at the UK premiere of John Adams's Doctor Atomic. It is a huge and terrifying piece, a truly modern opera, about the Faustian pact Dr Robert Oppenheimer made when he created the atom bomb in 1945. In an unforgettable scene set the night before the first explosion, he twitched and winced alone on stage, as if in a living nightmare, quoting John Donne's "Batter my heart...".

Here was perhaps the ultimate example of how in an effort to make a difference you can damn yourself for all time. Whatever the historical arguments in favour or against the action, his was one of the hands that is for ever bloodied. At the time the pressure on him from the government made his work seem heroic; when the test bomb went off at Los Alamos it was celebrated by staff there. The implications of what they had created were not fully apparent until later. Success can be much more dangerous than failure.

"Don't just do something, stand there" is not an injunction we are brought up to recognise. It is inimical, historically, to the Protestant work ethic. It will not improve society and it feels naughty even to suggest it. I know that I feel my Victorian antecedents whispering "shirker" in my ear every time I waste a day. But is this really the right way to live now? Perhaps this period of economic turmoil is a useful opportunity to change the paradigm. Failure is an option. It is much more likely that we should encounter it than success, and psychologically we should prepare to embrace it.

An alien reading our newspapers would think that only famous people experience happiness, since only they articulate it; the only time a non-famous person is included is when they are killed, or photographed unflatteringly in sombre shadows alongside an article headlined "MY BRAIN TUMOUR STALKER DEBT HELL." Lived experience tells us that this is a gross distortion of the truth; fame and glory are much more likely to spoil your life – casting into doubt friendships, love, family and everything that really matters – than to enhance it.

In fact, we have reached a point in society here where the average life is much more blessed than the extraordinary life, where today's idea of a mundane existence is actually one of the most exalted, healthy and sophisticated in history. To feel satisfaction too deeply can lead to the stagnation of social progress; perhaps withholding it is nature's way of keeping us going. So you have to learn to feel it, to savour the mundane. Let us now praise ordinary things, small pleasures and keeping your head down.