gold, page-661

Negative interests are bad for those that have their savings in cash, but are good for those who already have debts or invested in financial assets like stocks, bonds, real estate.

And yes I agree at some point the system is likely to break, because even if you make interest rates negative to incentivise people to borrow, it still only injects more credit into the system which will still be deflationary if people attempt to pay it back quickly...