Probably money, which you use to pay for the most important things in life, but what else? Why do you work?
Maybe you find that everyday work improves your brain, advances your career and gives you the chance to enjoy the company of colleagues.
But perhaps you find work stressful, debilitating and shapeless.
Possibly you think it’s all these things, rolled into one.
Nine months ago, the Prime Minister appointed Matthew Taylor to lead an independent review into working practices.
Why him? Well, Mr Taylor is the chief executive of the Royal Society for the encouragement of Arts, Manufactures and Commerce, better known to everyone as the RSA.
The RSA exists to come up with creative solutions to social challenges – and few challenges appear more pressing than the way in which our working lives are changing.
Image: Uber is also under the spotlight
On Tuesday, Mr Taylor will present his findings, and at the heart of them will be his analysis of the so-called gig economy – the mesh of flexible hours, short-term contracts and freelance workers.
If that sounds complicated, think of Uber drivers or cyclists in Deliveroo jackets, checking their phones to see what work is available and how much money they stand to earn.
They work flexibly, but they normally work for the same couple of companies.
And that raises a question.
To most people’s minds, these people aren’t employees in the traditional sense, but nor are they self-employed.
So Mr Taylor will suggest a new form of employment – what he will describe as a “dependent contractor” – and will also say that such people deserve more employment rights, such as sick pay, holiday leave and a closer tie to the minimum wage.
In short, he wants more clarity and more regulation, and that may well be the bit of this report that gets the greatest coverage.
But there’s likely to be plenty more that deserves both attention and, long-term, a policy response.
Look in the right places, and you can find plenty of clues as to the direction of Mr Taylor’s thinking.
In May he delivered a speech entitled “Good Work for All” – his report for the Prime Minister is called “Good Work”.
Image: Matthew Taylor is leading the review
In that speech, Mr Taylor outlines five different areas in which he thinks working practices could be changed.
Each of these, I would guess, will be in his report.
First is the need to develop better progress away from poverty, which he describes as “a moral responsibility”.
Mr Taylor says 13.5m people in Britain live in poverty, 55% of of them in a working household.
“Jobs,” he wrote in his speech “are not a guarantee against poverty”.
His second point is that “some work can make you sick”, with stress levels rising fastest among low-paid workers.
Third is the UK’s famously bad level of productivity – Mr Taylor says the country needs better management and more investment in training.
His fourth area is technology and the effect of the gig economy, which he says can “atomise workers”, while his fifth point is that there needs to be a stronger relationship between work and society – “why is the offer to consumers so much more ambitious than the one to workers and producers?” he asks.
These are fundamental questions about the UK economy, about the changing ways in which we work, the reasons we work, and how work affects us. The question is what will follow.
Mr Taylor’s report will, no doubt, be examined closely, particularly because the gig economy has recently bubbled up the political agenda, but also because our economic future now looks so volatile.
He has already said that he worries he won’t get a reaction, that his report will be seen as “empty posturing”, but that he will push hard for a public debate.
But the test will be whether policy changes, whether his recommendations are accepted and built upon.
Having commissioned this report in the first place, the Prime Minister will be under considerable pressure to respond to it.