G.K.Chesterton wrote "If a thing is worth doing, it is worth doing badly." The quote comes from What's Wrong With The World (lovely title); you can read more about the context here, at the American Chesterton Society. I don't disagree with the editor's comments on this, but am going in a different direction. Their commentary suggests that it is about things which people should do for themselves rather than leave to professionals, such as choosing mates, rearing children, and making laws. Interesting that we now try to leave those things to professionals as much as possible, eh?
My eighth-grade teacher, Mrs. Gladysz, used to say "If you don't have time to do it right, when will you have time to do it over?" The question may have hung on the wall as well. Ignore for today's discussion the obvious objections that fourteen-year-olds would raise, such as "I will have more time after basketball season." Her intent was inspire (or command) our best effort and praise excellence, which is precisely what we hire eighth-grade teachers to do. It nonetheless contains the seeds of a dangerous attitude.
A neglected measure of an act or an idea is how valuable it is even if done badly. If people are hungry they need food, and if you are not a chef or even a mediocre cook, so what? If the fire is spreading it must be put out; this is not the time to get training on firefighting. In these instances it is need that drives action. Fighting a war, praying, and calling home are things of this sort. They are things that it is important that they are firstdone, and only secondarily that they are done well.
This applies in the realm of belief or philosophy as well. Some ideas will get you farther even if done imperfectly. Marxists complain that real communism hasn't ever been properly tried, so we can't reject it yet. Well yes, it is certainly true that the various socialisms work better when they are done well, as in Scandinavia than where they are done poorly, as in Cuba or North Korea. But you will notice that there is a heckuva lot of non-socialism in the Scandinavian approach to other countries. They compete with other countries on the world market, and their success at that, plus their lack of internal corruption, allows them to enact a moderate socialism.
The free market, OTOH, provides a lot of benefit even when it's done badly. Italy gets by with a fair bit of corruption. We have more nepotism and exploitation in America, yet our poorest states and our poorest minority groups have more income than Swedes.
Christianity shows the same advantage. It has never been practiced perfectly, save once when God himself illustrated it. It has seldom been tried more than even half-heartedly on a large scale, yet it has provided the basis for most of what we call "good" in our society.
Christianity can be practiced so badly that it might have been better to not have tried at all, certainly. And good things twisted can produce great evil. But most of the complaints of wars and exploitation attributable to Christianity are ridiculously overstated. (For some evidence, though not proof of this see my earlier post on The Big Bad Three.) Sometimes the value of something is seen in how it works when done badly.