This year ought be a great moment in the history of work, by which I mean there shouldn’t be very much work to do. Eighty-five years ago, John Maynard Keynes predicted that the problem of future generations would be too little rather than too much work: not a bad problem to have. Technological development and compound interest would mean that we in the 21st century would be “only too glad to have the small duties and tasks and routines” of the rich, as paid work would take up an ever diminishing part of our time. We might be needed on the job for three hours a day.

While Keynes’s prophecy hasn’t come to pass, he was right in a sense: machines can do many things – more all the time – better, cheaper and more efficiently than people can. Algorithms write share reports for the Associated Press with a flat clarity; computer-controlled robot arms bend and weld the bonnets of Minis at the BMW pressings plant in Swindon. But in Swindon, and pretty much everywhere else, the robots’ human designers and repairers aren’t yet on a 15-hour week. Why have machines, and an evermore productive economy, led not to the world Keynes foresaw, in which work is a shrinking part of life, but to one in which work seems to be colonising life?

In the past, you could tell what work was partly because it consisted of tasks you wouldn’t do at home, where there are no crops to harvest or assembly lines to man. Economists think of jobs as belonging to one of three broad sectors: agriculture, industry and services. Agriculture employs very few people today, industry takes on far fewer workers than in the past, while the service sector has nearly doubled in size.

In 1948, teaching, nursing, retail, administration and so on employed 44% of the workforce; today, the service sector employs 85% of workers across the UK. This shift has meant two things for what work feels like in offices, shops and factories across the country: an upsurge in the sort of jobs that use our emotions instead of our bodies; and the crumbling of the divisions between work and life.

Over the last 50 years or so – when, not coincidentally, women have become a permanent fixture in the workplace – jobs have more and more required doing the sort of “women’s work” formerly associated with home life. Work increasingly consists of doing things you already do for love (for want of a better term), not money. Call centres, cafes, homes, boardrooms, classrooms, waiting rooms: working in these places demands caring, smiling, anticipating someone’s feelings or, indeed, changing them.

We know there is work behind the relentless cheerfulness we buy along with our morning coffee – an ex-barista describes stealing over-the-counter chat from a naturally sunny colleague and finding himself still asking: “Did you have a nice weekend?” on Thursday – but we don’t often think about what goes into that alacrity. Perhaps we don’t want to be scowled at when ordering a cafe creme, as can happen in Paris, but what’s the cost of the manufacture of feeling that, increasingly, we are all required to do?

What does work feel like now it has so much to do with feelings or, we might say, the presentation of feelings?

Women’s work – “care work” or “affective labour”, as academics often call it – is no longer just for women. The call-centre worker had to be good humoured and reasonable at all times, but also talked of being signed off with depression, of drinking more than he used to, of his son trying to convince him that work was closed today. The creative director in advertising had to leave her young son for several weeks while she shot an ad across four continents. She described her work as talking, “from the moment I get in until the moment I go home”. A social media entrepreneur relied on her iPhone calendar to know where she had to be every day and while her tote-bag office could be set up in a park or at a cafe or on a hot desk, she had to be instantly and always available for her employer.

For this is another way in which the boundaries between work and “life” have broken down. The working week refuses to get shorter and sometimes seems to have burst its boundaries altogether. Everyone who works in an office feels they must answer emails outside the office too, because jobs are no longer for life and we must constantly, and anxiously, prove ourselves. Work has become both less remunerative – wages are down 8% on 2010 – more pervasive and less secure. Labour’s plans to raise the minimum wage to £8 and end zero-hours contracts after 12 weeks address the practical problems but don’t get at the tendency of us all to become servants of the service industry.

Though no one I spoke to yet worked Keynes’s 15-hour week, I did find someone who worked only a 24-hour week, in two shifts. Ina, born in Bulgaria, has done sex work from a flat in central London for five years. She holds her two nights of work apart from the rest of her life: partly because not everyone in her life knows what she does, partly because that’s the way she sees things: “I tend not to take home my work,” she says. “Like even when you work in an office or a restaurant, don’t take it home with you, don’t take the stress with you at home.”

Beyond those two evenings, Ina saw friends, spent time with her boyfriend and studied for the career she wanted to pursue in care work. Whether through smartphones or zero-hours contracts, work has seeped into all the corners of our lives: we need to collectively resist the idea, as Ina does, that work is all there is and that workers are all we are. Not-just-workers of the world, unite!

Joanna Biggs is the author of All Day Long: A Portrait of Britain at Work