OF POLICY, MICE, MEN, & CUTTING BOARDS. UNINTENDED CONSEQUENCES

New York City prohibits cats in shops as a health hazard because of their fur, waste etc.
So - What do you end up with? Rats, mice, - rat fur and mice droppings - in your food instead.  And shopkeepers forced to break the law and pay fines. 
I prefer cats personally. 

Bureaucrats decide to ban in restaurants the age old practice of using wood for cutting boards. The result? Untold numbers exposed to higher levels of more dangerous pathogens (I worked in restaurants for years, and personally had to change cutting boards and wooden shelves due to these laws). Turns out no one thought to compare plastic cutting boards under real usage conditions against wood – in the real world plastic cutting boards become (surprise!) covered in cuts. In plastic, these harbor dangerous bacteria, while in porous natural wood they do not. Wood is safer in the real world.

In the 21^st century, in relatively small scale and well-defined areas of society (food practices in shops and restaurants), a modern country (the US in this case) cannot get cats and mice and cutting board policies correct. How well do you think larger bureaucracies governing much less well-defined situations in much more complex environments, often in countries and cultures far away, do?

Let us step up the complexity a little - say, to the still highly circumscribed (compared to studies of global development and entire societies) area of alternative fuels and their utility. Policy makers and many academics were in consensus that palm oil and biofuels were a good idea. But...
Once a dream fuel, palm oil may be an eco-nightmare
and
Biofuels make climate change worse
How, then, can anyone imagine that in the still more complex areas of social policy or international aid that the EU, World Bank, IMF, NGOs, the US Government (Katrina, anyone?) can do any better?

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(Related)

The Death of Common Sense: How Law Is Suffocating America.

Philip K. Howard. 1995. Amazon.