Put aside all your personal feelings about money - how much you make, have, save, spend, or need. Money doesn't mean anything, it is just a means of exchanging value so that someone who does plumbing for a living doesn't have to also grow their own food and mine the metal to make the pipes.
A market economy is decentralized, there is no single decision-maker that mandates how many plumbers need to exist or how much pipe needs to be manufactured. Those decisions are made by market forces I.e. profit.
The information about how valuable something, someone, or some skill is in a decentralized system is determined through transaction. Money needs to flow in order to get accurate prices for everything and determine their value - valuable things have a market price that exceeds their costs to produce/maintain/etc. The greater the liquidity in a market (and the lower the cost to transact), the more accurate this information.
Inflation incentivizes spending money - on goods, services, or assets, rather than holding the currency itself. It can be thought of as a tax for withholding participation in the market. It increases liquidity and facilitates price discovery.
Broad deflation - the price of everything falling - is generally a sign of economic collapse. It means that no one wants what the economy is producing at the prices it can sustain... so stop making everything... food, houses, etc.
Sector deflation is quite common - electronics (until recently) got cheaper for decades - and this generally reflects increasing production efficiency and healthy marketplace competiton (good). But people spending less on TVs need to find somewhere else to spend that money to keep the system operating. Reducing spend overall is the signal to reduce output, which means recession, unemployment, etc. Economic contraction makes everyone poorer.
None of this would be bad if the life of the median person wasn't balanced on a knife's edge over the abyss of homelessness and poverty. Against that backdrop, it can often seem cruel that the system is designed in such a way that everything gets more expensive all the time. If your earnings aren't keeping up with or exceeding inflation, however, it is the system telling you that the role is being culled. Find a new job (obviously easier said than done in most cases).