ECB's extravagance sparked fears that it knew about a nasty problem in European banking.

ECONOMIST: A liquidity squeeze

However, letting a nasty problem fester almost always guarantees a future crisis.

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If central bankers allow inflation expectations to become unhinged, they will have a nasty, protracted problem on their hands.

ECONOMIST: America's economy

It also means that whereas population growth may not be a global problem, it could often be a very nasty local one, causing conflict over local resources, especially water, and privation when politics (frequently) or natural disaster (occasionally) cause local scarcity or epidemic disease even within a wider world of abundance and improving health.

ECONOMIST: A Survey of the 20th Century

Politicians, especially liberals, have a nasty habit of creating government programs to solve problems, without knowing whether the problem exists, and, if it exists, how big the problem is.

FORBES: Krugman's Sick Numbers

"Google, because of the way it stores things, can perpetuate a problem, " says founder Craig Newmark, who recently spent an afternoon chasing a user who wrote six nasty messages about a neighbor.

FORBES: Google Me Not