Low self-esteem is behind a huge amount of unhappiness and, indeed, mental illness. A lot of behaviour that drives you mad in other people, from bullying to control freakery, can be fed or even caused by poor self-esteem.

The word self-esteem has become used much more frequently in recent years. When I was young, people used a different term to mean the same thing – self-worth. In some ways I prefer the old-fashioned term because its meaning is much more obvious. It’s about seeing yourself as being of value.

This sense of having value is something that everyone needs to be comfortable in their own skin. Some of us struggle with it more than others, and we all have times in our lives when it comes easier or harder. For example, your parents might have felt they were valued, important, useful when they were bringing up a family, but once the kids have left home and they retire, they might start wondering what use they are to anybody.

Some teenagers struggle with this because, especially in the West, they aren’t always expected to make a contribution – either to society or just to the family – so it’s hard for them to feel they have value. It’s the teenagers who have Saturday jobs, and do chores round the home, whose self-esteem benefits.

You’re not responsible for anyone else’s self-esteem – so long as you’re not undermining it – but it’s useful to understand that this is a feeling everyone needs. Even your overbearing, charismatic, confident colleague. Maybe they already have a healthy sense of self-worth, but if it was undermined and taken away, they’d suffer badly.

A lot of people don’t recognise when they are valued, especially if they’ve learnt, for whatever reason, to doubt their worth. Most of us need to be told to be really sure of it. So if you want to make someone feel good about themselves, let them know when they’ve been helpful, useful, valuable. A thank you is OK, a bit more than a thank you is better: ‘Thanks. I don’t know how you did that so quickly, but it’s made my day a whole lot easier.’ The more specific you can be about what they did, the more genuine and believable it is. That’s why a mere thanks is better than nothing, but only just.

You’ll also find that people are far more likely to co-operate with you if doing so makes them feel good about themselves. That’s a win/win. So make sure you give people credit when they’ve added value. They’ll want more of that good feeling, and you’ll get the help you need plus the feeling you’ve added a few drops to someone’s self-esteem bucket. Why wouldn’t you want that?