> How do we identify good times

By looking at the employment rate, not the meaningless unemployment rate numbers. https://tradingeconomics.com/united-states/employment-rate

> How do we get humans to save in good times.

By electing people that save responsibility. Post WWII the US paid down huge amounts of debt. Now it seems like Republicans want to loot the place whenever they get power and Democrats are willing to trade spending for more spending.

The EU via the EMF have been doing aggressive QE upon the Euro for years now, just to keep the EUro competitive for exports as well as imports. A high euro value makes imports cheap, but kills exports as they come more expensive export wise. A low currency makes imports expensive, but makes exports cheap.

So they have been interjecting to keep the balance right.

Before QE you had country interest rates, but with many of those low, the new tool on the block is negative interest rates.

Sadly all these have produced two decades of fiscal responsibility that has seen saver mentality die and buy today, pay tomorrow increase. Which i'm sure looks great on some balance sheet and allows politicians and accountants to say hey, look at the growth, ain't we doing well and the market perception just nods and agree.

Any dent in that perception and a whole raft of cards quickly start to fall and with that in mind, interesting times ahead and let us see what happens.

That fiscal stimulus should be counter-cyclical isn't "Keynesian economics". It is just macroeconomics.