Sometimes cutting interest rates to zero still can't get people spending

John Maynard Keynes described a scenario where interest rates fall so low that everyone would rather just hold cash than lend it out or invest it, since the returns aren't worth the trouble. In that state, a central bank can pump in as much money as it likes without stimulating the economy — monetary policy simply stops working, and only government spending can pick up the slack. Japan's near-zero rates through the 1990s and 2000s became the textbook modern example.

— John Maynard Keynes, The General Theory of Employment, Interest and Money — 1936