From David Stove's essay, "Why You should be a Conservative:"
A primitive society is being devastated by a disease, so you bring modern medicine to bear, and wipe out the disease, only to find that by doing so you have brought on a population explosion. You introduce contraception to control population, and find that you have dismantled a whole culture. At home you legislate to relieve distress of unmarried mothers, and find you have given a cash incentive to the production of illegitimate children. You guarantee a minimum wage, and find that you have extinguished, not only specific industries, but industry itself as a personal trait. You enable everyone to travel, and one result is, that there is nowhere left worth travelling to. And so on.
This is the oldest and the best argument for conservatism: the argument from the fact that our actions almost always have unforeseen and unwelcome consequences. It is an argument from so great and so mournful a fund of experience, that nothing can rationally outweigh it. Yet somehow, at any rate in societies like ours, this argument is never given its due weight. When what is called a 'reform' proves to be, yet again, a cure worse than the disease, the assumption is always that what is needed is still more, and still more drastic, 'reform.'