It's easy to put off thinking about the meaning or purpose of one's life but, if we do, we're simply setting the scene for a disappointing climax.

A Porsche; a mistress; a new gym membership; a holiday home in Spain; a move to the countryside; a new career, perhaps as a herbalist or a bee-keeper. What do each of these things have in common? They are each a potential knee-jerk reaction to a mid-life crisis. But what is a mid-life crisis, and why do we have them?

It is all too easy in modern life to “go with the flow” - to simply put up with whatever situation you find yourself in, irrespective of whether it suits you or whether it makes you happy. Few people are prepared to challenge themselves by moving to a new city or country; re-training for a new career; or finding themselves a new life partner if the status quo does not please them. However, whilst putting up with an unhappy or unfulfilling job or home-life might be considered by some as stoic or dedicated, the reality is that (more often than not) that situation is building up feelings of resentment, unhappiness and longing (for change; for challenge; for meaning) in the subject of that life.

Life can be a roller-coaster ride: it's full of exhilaration; trepidation; and turbulence – but it's also over in a flash. The path from school, to college or University into a career; a relationship; home-ownership; and then a family is well-trodden. If we don't make time for ourselves – to look up once in a while from our daily grind; to consider who we are and who we want to be – then it's easy to put our heads down at school and not to pick them up again to look around until we're 45 or 50, married with children and stuck in a job we don't enjoy. By that time, we may well feel that the best years of our lives are behind us – squandered on meaningless activities, pastimes, and relationships that haven't actually given us what we want from life. The feelings of disappointment, frustration and even anger can then make us feel as though we have lost all direction in, and control over, our own lives.

Led by marketing men seeking to persuade us to buy products that we don't really need; coerced by peer pressure and credit card companies to borrow money we'll struggle to re-pay; and trapped by convention and social expectation to remain in our soul-destroying and unfulfiling jobs, that moment of nirvana when we finally see through it all to understand that none of it gives our lives meaning, and that all of it is just a distraction from what we really need to be happy, can be a seismic, life-altering event.

Sooner or later, the inevitable thoughts about our mortality creep into each of our minds: life is short;  nobody knows how to make me happy except me; once I am dead, all that remains of me, who I was, and the life I have lived are my memories, and the stories and details that I shared about myself with others.

That's a stark message, and one that many of us want to ignore for as long as possible. But that's exactly the problem: we can ignore what life is really about for much of our lives – but eventually we have to face up to who we are; the lives we have led; and whether we have set out to achieve what we hoped to do. The sooner we make time to contemplate our existence, and the meaning and purpose of our lives, the sooner we can make the necessary changes to our lives to make sure that we understand how we want to live; what we want to do; and what we want to be remembered for doing.