Groceries, sure, but then as a consumer you are still impacted because suppliers are less likely to provide the goods you want.
Deflation is really bad. One of the consequences of the gold standard was the big swings (inflationary after a big gold strike, like California' Yukon, or Victoria; deflationary when the gold supply could not keep up with economic activity) that you can easily see in the second half of the 19th century.
Businesses don't collectively decide to reduce prices month after month out of generosity. They do it because the economy is in a position where none of them are selling enough at the current price. If everyone is selling less stuff at lower prices, then sooner or later the problem becomes the employees'...
This will obviously not mean skipping eating, but will manifest more as fewer "special" meals like steak or lobster or whatever.
> a fridge, a new roof
If you are a homeowner, you know that most equipment failures are a decision to either repair or replace. In a deflationary environment, owners will bias toward patching things as long as they can. (The opposite is true in an inflationary environment.)
> a new car
You may be extremely fortunate. Most people would try to make it through (say) a year of public transit/rideshare/etc. if they could save (say) 8% on a car. Average price of a new car in 2022 is ~$48k; saving 8% on that is something like half a month's pay at the average American salary, which is larger than the annual raises most people get at even good jobs, even in good times. Don't underestimate the sacrifice people will make to earn another few hundred $/mo.
So if we live more sustainably, the economic system colapses?
Is that a bug or a feature?
I just had my landlord throw away the dishwasher because replacing the tiny pump was not worth the effort. Myfriend threw away a fridge because replacing a single part, the compressor, was not worth the trouble.
So, I'm with you. I've had it explained to me many times, and it still doesn't make much sense to me. I'm going to buy cars / houses / investments / goods / services when I need them and can afford them-- not based on speculation about their future prices (well, except for investments, if I have some magic insight).
From a business perspective, I've been involved in many purchasing decisions and never once was "it might be cheaper or more expensive in the future" a part of the decision making process.
It really feels like "deflation is bad" is an economic theory that should be tested. Yes. We've had deflationary shocks, and those were bad, but that was because a) it was a shock rather than a gradual slope and b) it usually followed a period of marked excess. I'm not convinced that deflation itself was the enemy as much as the other ancillary issues. It's hard to disentangle that, though.
Think about the prevalence of sales, and their impact on moving goods. If you need a TV, but the need is not urgent, you (okay, not you, but most people) might wait for the New Year's sales in a couple of weeks to save a few bucks. Same with cars and other appliances. Or people look for a coupon code to save some money.
If sales and coupons make sense, consumer decision making in deflationary environments should also make sense. If you don't understand why people wait for sales to purchase things, you may want to talk to some working-class people to understand what it is like to not have enough money to buy everything you need immediately when you need it.
> it was a shock
Japan has been in a gradually deflating environment for decades.
I'm not saying this conventional wisdom is wrong, but it's not obviously right.