"The Best is the Enemy of the Good"? If so, how about, "The Worst is the Friend of the Bad"!
It makes a cute meta-proverb, anyway—and maybe it actually has a bit of meta-wisdom behind it. "The Best is the Enemy of the Good" means that a go-for-broke accept-no-substitutes pursuit of perfection is likely to result in something less, maybe much less, than one could have achieved—perhaps not even "good". Similarly, an extreme risk-avoidance policy focused on preventing worst-case scenarios will also likely result in something far less than the optimum—perhaps not even a "good" outcome.
Or then again, maybe over-analysis just spoils a joke ...
^z - 2008-10-28