Policymakers have a frightening habit of putting what they would like to see, or what they feel would look good on their CVs, over what is realistically achievable.
This is not a peculiarly South African problem and history is replete with examples of ideas that sounded good at the time but turned out disastrously.
The US had prohibition to counter the negative effects of alcohol, but wound up enriching gangsters and entrenching the mafia's place in daily life.
Zimbabwe's leaders tried to deal with skewed land ownership patterns but ended up starving their people, killing their economy and ensuring that they earn a place in history reserved for dictators and abusers of basic human rights.
William Buckley jnr, the darling of US conservatives and septuagenarian columnist, said "idealism is fine, but as it approaches reality, the costs become prohibitive".
I don't know what prompted this particular pearl of wisdom, but it is applicable to modern South Africa.
We have, over the past decade, developed a suite of policies that comply with international best practice and, often, break new ground. Our legislators are now able to tell the world how the laws they enact do this, that and the next thing for the environment, social justice and the economy.
And while there have been some notable successes that have, before anyone has a go at me, been given their share of space in this column, it is clear other policies have either failed outright or have given rise to a host of euphemistically termed "unintended consequences".
The US's 31st president, Herbert Hoover, said - and again this is apposite to the South African case - that "words without actions are the assassins of idealism".
And he was an expert on idealism. According to the online Encyclopedia Americana, when Hoover decided to go into politics after a very successful career in engineering, he campaigned for both the Democratic and Republican presidential nominations before declaring that he had always been a Republican.
Closer to home, a classic case of pragmatism being overtaken by idealism was the recent debacle surrounding the introduction of rules governing the use of plastic bags.
Driving through parts of the Eastern Cape, it is clear why the thin plastic packets were seen as the national flower in some parts, and anything that rids us of the blight on our landscape is a good idea.
But the way in which it was done - with tens of thousands of jobs being put at risk in a country where millions have no short-term prospects of finding work - was just plain dumb. Rather than banning the bags, wouldn't it have just made more sense to pay people to recycle, as is done with aluminium cans?
And then there is the whole issue of anti-smoking legislation. As a rabid non-smoker, I like the idea of eating in a smoke-free environment. But this was always easy to achieve - if a restaurant was unable to give me what I wanted, I didn't eat there. This was a simple and elegant solution, I thought, and there was no need to introduce a set of laws to protect me. And these laws just raised the costs of doing business - never a good thing.
Another case of putting what policymakers would like to see over the practical realities of what is feasible is looming with the deadline for phasing out the use of lead as an additive in petrol. The government has said refineries must produce lead-free petrol by January 2006 to minimise pollution levels.
Econometrix director Tony Twine has said that one in three cars will be unable to use unleaded fuel, and that the set date is too soon given that older cars will make up an estimated 33 percent of the fleet in 2006.
If the government's wishes are met, thousands of cars will be taken off the road, damaging the livelihood of garage owners, mechanics and spares shops.
As a country, we can't afford to lose any more jobs and there is too much that needs to be done in the short term to say we can easily afford Twine's estimate that it will cost between R13 billion and R15 billion to remove lead from the fuel supply. Rather, steps can be taken to reduce tariffs and find other incentives for people to upgrade their vehicles.
Then there are the thorny issues of the laws surrounding drugs and prostitution. The reason sex and narcotics are for sale is that people want them and are prepared to pay handsomely for the privilege. The laws and policing structures put in place to stamp them out are simply ineffective.
Stupid laws - either because they are unenforceable or because they just don't make sense - get ignored. All the authorities can do is try to minimise the transgressions. This requires pragmatism, common sense and a determination to ensure that only those laws that make sense and are enforceable remain on the statute books.
The rest must be filed in the nice-to-have folder to be dusted off when they can be properly implemented. Till then, they will remain an expensive millstone around our necks.