Times have changed.

I think a daytime meal with friends — brunch is quicker, cheaper, less boozy than dinner — should be uncontroversial.

But the very concept of brunch is enough, apparently, to make my dad furious.

“Brunch?!” he says, enunciating the word with disbelief and contempt, as though this is the final straw in the moral decline of modern Australia.

This, mind you, is a man who held an office job through the era of the long lunch.

Similarly, a colleague informs me their mother hadn’t been to a restaurant by the time she was 18. Not even once.

Precisely the sort of thing the older generation enjoys reminding you of if you breathe a word of complaint about house prices.

But don’t worry. This is not another piece that flings blame and tries to exploit sentiment about millennials or boomers ruining the world. This piece explains why the generations are at each other’s throats — even more than normal.

The lives of younger Aussies are so different to the lives of their parents at that age that they may as well be from different cultures.

“BRUNCH?”Source:Supplied

This is the first time in history technology and the economy have both been changing so fast. We don’t have practice at dealing with this pace of flux.

Young people look with jealousy at a generation that had free university education and houses you could buy on one ordinary person’s wage.

Older people look with despair at a generation that seems to spend their whole time on a mobile device but don’t have their driver’s license.

This is how history has always worked, just sped up.

In 1790, Reverend Enos Hitchcock argued vehemently against books:

The free access which many young people have to romances, novels, and plays has poisoned the mind and corrupted the morals of many a promising youth.

In 1859 Scientific American laid bare the risks of chess. Yes, Chess:

A pernicious excitement to learn and play chess has spread all over the country, and numerous clubs for practicing this game have been formed in cities and villages ... chess is a mere amusement of a very inferior character, which robs the mind of valuable time that might be devoted to nobler acquirements.

Articles that now seem that silly could be written only every few decades then, but now, you could write one every week.

Older generations barely have time to get upset about Facebook before it is time to worry about Snapchat.

Whether it’s cold-brew coffee, online poker, Netflix marathons, driving for Uber, methamphetamine, Tinder, fixies, or living at home until you’re 28, there’s an unprecedented array of new trends on which a grouch could pin the decline of civilisation. (Some of which, to be fair, could genuinely cause the decline of civilisation.)

A quick dive into the data shows dozens of ways in which times have changed massively and my favourite is this one, which must have barely seemed worth including back in 1984: “Health and fitness studio charges”.

Households spent just 17 cents a week on that quaintly titled category in 1984. That has risen 15-fold to $2.71 a week by the most recent data (2009-10).

The gym (and its close cousin the gym-selfie) are a major part of the new economy, which is all about services, rather than goods.

It’s much more about services than goods today.Source:Supplied

Spending on overseas holidays grew five-fold, and spending on phones grew about the same.

Live theatre is of a bygone era, it seems. Expenditure on it grew far more slowly than inflation.

Spending in 1984 compared to 2009-10. Source: ABS.Source:Supplied

Phones are another huge new category of expense. Whereas households once spent about as much on men’s clothing as phone bills, they now spend almost six times as much on phones.

That is partly because men’s clothing has become cheaper, and because men tend to wear less formal clothes.

But the graph above shows in many ways, these days we are more restrained. Expenditure on beer and gambling has risen less than inflation.

I have to confess the “meals out” category has risen faster than inflation. Is brunch to blame? It might be.

It’s not like I’ve actually stopped going out for dinner in order to go out for brunch. Maybe my dad was right?

Jason Murphy is an economist. He publishes the blog Thomas The Thinkengine.

Follow Jason on Twitter @Jasemurphy