Most people want more investment in renewables and some people want more investment in coal-fired power stations. Given that we don't need both, the political fight about which technology to invest in will have a lasting effect on the shape of our economy. It's no different from the debate about removing trams from Sydney back in the 1960s and the debate about building light rail in Canberra in 2015. All investment decisions "create jobs", but only some investment decisions build the society most of us want to live in.

When it comes to our personal lives, we all know it's the quality of our spending decisions, not the amount of money we spend, that matters. For example, when buying clothes, most people choose clothes in the style they like and in a size that fits. And while it's possible to simply tell the shop assistant you would like $1000 worth of clothes, most people would think that's a bit odd. It's the same with ordering food at a restaurant. While you could walk in and order one kilogram of dinner, or $100 worth of dinner, most people choose instead to specify the kind of food they want to eat. The point of the menu is to present us with valid choices; it's our job to match what we feel like with what we spend. Again, it's what we buy, not how much we buy, that matters.

But when it comes to the economy, Australians have been told for decades that as long as the amount of stuff getting bought is growing, we must be doing well. While there is no doubt that opening new asbestos mines would lead to an increase in GDP in Australia, there is no evidence that selling more of something that harms us would make us "better off".

So despite the fact that growth in some activities makes us better off and growth in other activities makes us worse off, many politicians and business leaders in Australia have become obsessed with the idea that, as long as the total amount of stuff being produced is growing, we must be better off. Just think about how often you have heard a politician or a business leader say we need to "grow the economy" without saying which parts of the economy they want to grow. Indeed, think about the number of times you have heard a politician say we need to shrink parts of the economy that people want more of, like the health sector and the education sector, to grow the economy overall. What a strange idea.

It gets worse. In recent decades, we have been told repeatedly that spending money on imported stuff that we never use is "good for the economy" because it is "good for the retail sector" and "creates jobs". The argument is as rubbish as the tonnes of unused stuff that we then need to bury in landfill.

It's obviously true that if Australians all choose to increase their spending on new phones, new toasters and new exercise bikes, that the shops that sell phones, toasters and exercise bikes will make a bigger profit. They may even employ a few extra staff. But that isn't the same as "creating jobs" for the simple reason that every dollar spent on an exercise bike that was never used is a dollar that wasn't spent on a maths tutor, a personal trainer or some smashed avocado at the local cafe.

Wasting money on stuff we don't need doesn't "grow the economy", it reshapes the economy such that the retail sector grows and some other part of the economy misses out. And it is the shape of the economy, not its size, that has a big effect on our well-being, our unemployment rate and the amount of harm we do to the natural environment.

Imagine a person spending $1000 on discount electrical goods, compared to spending the same amount on massages, locally produced food, tickets to a play and a dinner in a local restaurant. While the total amount spent is the same, and the effect on GDP is the same, the effect on Australian jobs, and on the natural environment, is entirely different. Put simply, because some activities create more jobs than others and some activities do more environmental harm than others, it is the shape of our economy that determines whether we create jobs or increase greenhouse gas emissions, not its size.

Of course, it's not just individual spending decisions that determine the shape of our economy. When the Turnbull government decided to increase subsidies to the Adani coal mine and cut subsidies to renewable energy, it decided to reshape the economy in ways that will reduce employment and increase greenhouse-gas emissions. And when the ACT government decided to invest in light rail and offer incentives to people to drive electric cars, it reshapes the economy in ways that increase local jobs and reduce greenhouse-gas emissions. Choices matter at the ballot box and at the checkout.

But despite the fact that every time we spend a dollar, take a job or cast a vote we help to reshape the economy, many people have come to believe that it is "the global markets" that decides the shape of our economy rather than ourselves. Take cafes, for example. In the first 24 years of my life, I had never once been out for breakfast. But since my first experience of letting someone else cook my eggs, I have never looked back. And I'm not alone.

In the last 20 years, the number of people in working cafes, restaurants and bars grew from 460,000 to 780,000. It wasn't the global markets that reshaped our morning, cities and caffeine intake – it was us. And in response to millions of people wanting to spend a lot of money paying others to make them breakfast, we not only created a lot of jobs, we created what we now call cafe culture.

So imagine what would happen if millions of people shifted their spending decisions away from imported stuff towards locally produced goods or locally provided services. It wouldn't shrink the economy; it would reshape the economy as radically as our recently discovered penchant for labour-intensive coffee did.

Now imagine that millions of people got into the habit of maintaining their stuff, repairing it, repurposing it and finding a new home for it when it was done. Imagine if people rediscovered the benefits of buying second-hand goods. And imagine if you could get your stuff repaired at a repair cafe that sold you great coffee while you waited.

Such a world is no more impossible, and no more unlikely, than a world Iike ours, in which people pay $10 a litre to buy bottled tap water and throw away tens of millions of plastic bottles because they can't remember they get thirsty every day.

Changing the world isn't hard – it's inevitable. The consumer culture we take for granted today didn't exist 50 years again and it won't exist in 50 years time. Whether the Australian economy evolves in ways that increase the availability of making jobs or selling jobs will not be determined by the "global economy", it will be determined by the spending decisions and voting decisions that Australians make. But while changing the world might not be hard, predicting the direction of that change is impossible. I wonder what we will do?

Richard Denniss is The Australia Institute's chief economist. His latest book, Curing Affluenza: How to buy less stuff and save the world, was launched by Andrew Barr this week. Twitter: @RDNS_TAI