I've mentioned Richard Gabriel's famous The Rise of "Worse is Better" before (back here), but only recently did one of its important lessons coalesce in my thoughts.

"Worse is Better" contrasts what Gabriel calls the MIT approach, with the cornerstone of 'the right thing', against the New Jersey approach, with a 'worse is better' minimalism (this is a simplified summary). Gabriel argued that despite its flaws, the New Jersey approach had significantly better survival characteristics than the MIT approach, for reasons he described and I'm not going to try to repeat here.

The MIT versus New Jersey divide can be portrayed as a choice between the right thing and a so-so thing that's maybe good enough. When you put it that way, a lot of people will naturally tilt towards the MIT approach; who doesn't want to do the right thing? But this is wrong.

The perfect is the enemy of the good. - Voltaire

In reality it's not actually a choice between right and worse; it's really a choice between nothing, worse, and right. And over and over, aiming for right has been an excellent way to wind up with nothing (for reasons that Richard Gabriel outlines nicely).

The easiest place to see this is computer security, where insistence on perfection (or some excellent approximation) is one of the holy tenets. As a result we have a few very secure systems and a lot of almost completely unsecured ones.