''Be careful what you ask for, you might get it.''

''We can never do just one thing.''

''Outlaw "adult establishments", and you get strip-joints that welcome children.''

This is true. Local city revoked liquor licenses for all strip joints in city limits. The businesses just started charging $4/drink for soda, and opend their doors to 18 year olds.

''My mamma said not to put beans in my ears...'' (Pardon?)

Why is shark.armchair.mb.ca systematically introducing typos to pages?

''It's not. See SharkBot and GrammarVandal.''
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Other examples of unintended consequences...

	* Gateway's experience with Tech Support. (http://www.business2.com/articles/mag/0,1640,11434,FF.html)
	* Public housing, which concentrates and increases poverty because it moves poor people to where there is no employment.
	* Highway and street construction, which just causes the expansion of car usage to match.
	* Government loans to Russia provided it the foreign cash to import superior Western goods for the same price as domestic goods. This led to the bankrupting of even salvageable companies and decimated the Russian economy, which eventually led to starvation and death for millions.
	* PrisonersDilemma; acting selfishly is the worst possible selfish move.
	* War; initiating it practically causes you to lose it. (But if you do it over and over, never learning from history, one starts to wonder whether the consequences aren't intentional after all.)

The law books are full of laws that actually produce the OPPOSITE effect of what they were intended to combat...

If laws have the opposite effect to what they were intended to combat, then why do we make them? Some laws clearly do work: e.g. don't murder others. Other laws don't: e.g. don't take drugs which, yes, stops many people from taking drugs, but unintentionally fuels a massive crime wave. How can we distinguish between the two types of law? Here is a straw man: Laws that attempt to prevent direct harm to others are OK, laws that attempt to prevent direct harm to the individual are not OK.

The book "Measuring and Managing Performance in Organizations" by Robert D. Austin, Timothy R. Lister, Tom DeMarco http://www.amazon.com/exec/obidos/ASIN/0932633366/002-6003781-2904803 has some very interesting examples of UnintendedConsequences.

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See also: WhatYouResistPersists