These are the lessons of life. Always tinged with sadness and with only fleeting happiness.

We are herd animals. We're comfortable in herds of about seven or eight, and uncomfortable outside them. This is why work-groups of that size function so well; it's why seven or eight people is a good span of management control; it's why dinner parties of more than about eight tend to fragment.

The shrinking Australian household is no longer robust enough to satisfy our herd instinct, which is why we have to look outside the domestic herd for groups to attach ourselves to - cooking classes, book clubs, sports associations, adult education courses. We like grazing with the herd in cafes and food halls. When all else fails, we can even herd electronically (as our kids are doing with a vengeance).

Being herd animals, we need leaders. When leaders are strong and visionary, we feel confident and powerful. When leaders are weak or cynical, or when they are clearly more interested in their own power than our wellbeing, we feel uneasy, disengaged and powerless. Leadership vacuums tend to be filled either by demagogues or by our own unbridled self-interest.

We are irrational creatures whose behaviour can rarely be explained by logic. We act on impulse; our brains are awash with hormones (more like glands than computers); we do things we say we'll never do; we sometimes disapprove of our own actions, but go ahead anyway.

Our moral codes are subjective and flexible: even the Golden Rule, which we claim to have enshrined in our moral system, is distorted, in practice, into something like "treat other people the way you think they'd probably treat you" - a virtual contradiction of the original idea.

The deepest of all our needs is the need to be taken seriously as individuals. The other things usually described as basic drives - sex, power, the need to belong - actually flow from that one, central need. If you doubt it, look at what happens when people feel as if they are not being taken seriously: they become angry, depressed, cynical, aggressive or petulant, to say nothing of plain unhappy.

There's rarely just one cause of unhappiness or of its more brutal cousin, depression. But, somewhere in there, you'll usually find a person who feels under-valued, unappreciated or misunderstood. Not being taken seriously - by your partner, your bank, politicians, your colleagues, your parents - feels like the ultimate insult. (Not being taken seriously by your children is merely par for the course.)

If this need is as fundamental as I believe it is, that may help to explain why so many people take themselves too seriously: "If other people won't take me seriously enough, I'll do the job myself." So one reason for giving people the recognition they crave is that you might rescue them from the lonely descent into hubris.

I've discovered that everyone's story is interesting: if you think you know someone who's boring, that just means you haven't got to know them well enough. I've also come to realise that everyone's story is tinged with sadness; happiness visits most of us but fleetingly.

I've learnt to despise intellectual arrogance, because it fails to acknowledge the genetic accident that makes some people less intelligent than others. I've learnt to be suspicious of people who've made a lot of money in a short time. Too often, it turns out that they've cut moral corners, exploited others, charged unconscionable prices for their goods or services, or simply been devious in their business dealings.

Poverty is a blight on society, but I have acquired the deepest respect for people who work long and hard and manage to live responsible, generous and fulfilling lives without ever achieving the kind of material prosperity that rich people take for granted.

I've also decided that the meaning of our lives is to be found in the quality of our personal relationships and nowhere else. We are all part of the same humanity. We learn our most valuable lessons from each other.