Low inflation is one of those good things you can have too much of.
A strong disinflationary tide is running in the global economy.
The euro area is in outright deflation, consumer prices having fallen 0.2 per cent over calendar 2014.
In the same period they rose just 0.8 per cent in the United States, compared with an annual inflation rate of 2.1 per cent six months ago, while in China inflation has weakened from 2.3 to 1.5 per cent over the past six months.
And last week the Swiss National Bank abandoned its currency peg to the euro, adopted in 2011 to counter the deflationary effects of a soaring Swiss franc.
What that capitulation demonstrated, said Nobel laureate economist Paul Krugman, is just how hard it is to fight the deflationary forces now afflicting much of the world.
"You really, really shouldn't let yourself get too close to deflation. You might fall in and then it is extremely hard to get out," he said.
The Japanese can attest to that.
Deflation is regarded as a bad thing for a couple of reasons.
If it becomes embedded in people's expectations that prices in general will continue to fall, they are more likely to put off buying something on the grounds that it will be cheaper next year.
That is bad for business and for employment. For tax revenues, too. Weaker than expected inflation is one reason why the Treasury doubts we will see a return to fiscal surplus this year.
And chances are that the resulting reduction in economic activity makes people more risk-averse, reinforcing the effect.
The other ill effect is to increase the real burden of debt. Existing debt has to be repaid in dollars that are more valuable (in terms of purchasing power) than those which were borrowed and even if nominal interest rates are very low, in real terms (adjusted for price changes) they may still be too high for a stagnating economy.
So with the annual inflation rate having fallen to 0.8 per cent, should New Zealand worry about slithering into a deflationary bog?
At this stage, no.
That is despite the fact that we should never underestimate the ability of what is happening in the other 99.8 per cent of the world economy to sideswipe us.
Nearly half the consumers price index is made up of tradeables - items whose prices reflect global prices and the exchange rate.
In the course of 2014 they fell 1.3 per cent, offsetting a 2.4 per cent rise in domestic or non-tradeables inflation.
In the December quarter 36 per cent of the CPI by expenditure weight fell in price while 55 per cent rose - but the falls were larger than the rises on average, at 3.6 per cent and 2 per cent respectively.
In Statistics New Zealand's most recent retail trade survey, nine of the 15 industries into which it divides the retail sector recorded prices lower than they had been a year earlier, and indeed nine recorded prices lower than they were four years ago.
So it is not all about the plunge in global oil prices.
Petrol prices, which make up 5 per cent of the CPI, were 4 per cent lower in the December 2014 quarter on average than they had been a year earlier, which shaved 0.3 percentage points off the annual inflation rate.
But Statistics NZ said that if petrol prices stayed where they were this week for the rest of the current March quarter, it would make a downward contribution to the quarter's CPI of 0.8 percentage points.
"The real fireworks will come in the March quarter," says Westpac economist Michael Gordon. "Based on current fuel prices annual inflation could come in close to zero in the early part of this year."
The Bank of New Zealand's head of research, Stephen Toplis, argues that deflation caused by falling oil prices is probably not something to worry about.
It is not the kind that portends weaker consumption. People do not delay fuel purchases in the expectation of lower prices. They just have more to spend on other things.
But Toplis also points to a more pervasive and persistent disinflationary effect at work: "The combination of internet selling and relatively cheap and efficient freight systems is having an unprecedented impact on the price and availability of the goods and services that we now purchase. No longer is the competing price the retailer down the road but, rather, the distributor anywhere in the world."
The upshot is that tradeables inflation is less and less influenced by domestic demand conditions - which in any case are more robust in New Zealand right now than in, say, Europe - and more and more influenced by global spare capacity on the supply side.
Constrained pricing power is evident in this week's quarterly survey of business opinion from the New Zealand Institute of Economic Research. Fewer firms reported that they had raised their prices in the past three months despite more saying their costs had increased, and their expectations for the next three months continue that pattern.
But downward pressure on prices which reflects excess supply elsewhere in the world or consumer-friendly structural technological change is quite different from the pernicious, self-reinforcing deflation that Europe is in danger of and that has dogged Japan for 20 years.
History suggests New Zealand households are not all that thrifty.
"Instant gratification takes too long" is more like it.