The part-time and temporary jobs I had while growing up were a vital part of my education. There was an authenticity about them that sitting in a classroom entirely lacked. They helped to teach me the importance of a work ethic, independence, and just how tough many real workplaces are.

I worry that too few 21st-century teenagers get this type of experience – and that they are less well-rounded as a consequence.

I can recall sitting in the bath after my first day's work one Easter holiday in the late 1970s. The job was in a small engineering workshop. My task was to turn metal rods on a lathe all day. By 5pm on my first day my hands were blistered and raw.

Although I went to a state school, I enjoyed a comfortable upbringing and had never experienced a proper labouring job. But at the end of the week I got my pay in cash in a brown envelope with a cellophane window. It was about £40. Earning all that through my own efforts was hugely satisfying. It made me feel almost rich, and grown up.

Every Christmas I used to work as a temporary postman in my village, helping to deliver the seasonal avalanche of parcels and greeting cards. This was before the internet and mobile phones, so the Royal Mail was a much more important way to keep in touch than it is now. You had to start very early, but you generally finished your round by lunchtime.

The worst aspect was rain. If it was wet, you still had to finish the task, even if it took four hours. You ended up soaked, and your post wasn't much better. I remember being tempted to chuck a lot of post away on one day, but was reminded that doing so was a very serious offence.

I think of postmen struggling in the rain every time I drive by the splendid Eighth Avenue general post office in Manhattan, and see the evocative inscription, which reads: “Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds.”

Another summer job was working in a pharmaceutical factory making lubricant jelly. At that age I was only vaguely aware why people used it. I was shocked at the lack of ambition among the staff. None of them saw what they did as a career: it was simply a way to earn a living. They swore all the time – including the women – and most of them hated their jobs. Nevertheless, I enjoyed their company.

But I realised that finding something to do that you love from Monday to Friday was a vital ingredient to a fulfilling life. It became a mission of mine to pursue obsessively a livelihood where I could look forward to Monday morning rather than dread it.

As a first-year undergraduate studying medicine, I worked at St Mary's Hospital in London for an eminent professor during the vacation. He was studying the connection between cardiovascular disease and extended use of the contraceptive pill. I was a lab assistant and my boss was something of a tyrant. My main role was to analyse human excrement. It helped put me off medicine as a vocation, and indeed working for other people.

While I was at university I worked as a DJ for a mobile discotheque, spinning the discs at everything from student gigs to weddings. Once I gained confidence, I acquired my own turntables and loved the combination of working hard, playing music, meeting girls and earning money. I realised that being an entrepreneur was the answer – you could control your own destiny and you received the rewards for your efforts. With partners I ran weekly dances at a local nightclub. It made money from the start, and I saw that running a business could give you enormous freedom and creative stimulation.

For me, holiday and student jobs provided lessons in life and an insight that academic, formal education could never match. I wonder how many children of the readers of this column will have paying jobs while studying? Not enough, I fear.