I used to think optimization was a great idea. And it is, as long as you optimize single processes. But nested or contingent optimizations are extremely unwise. Go for robustness instead.
What changed my mind? Vernor Vinge. He’s one of the greatest writers I’ve ever read. It’d be wonderful if he was more prolific, but that’s just being greedy.
Anyway, his epic novel A Deepness In The Sky deals with advanced societies’ temptation to optimize everything in relation to everything else. What happens when some element, inevitably, fails? Catastrophic collapse.
Here’s an example from our own civilization. Fortunately the idea never gained headway. You could maximize crop yields by find the most productive plant and cloning it. But when a crop disease finally and inevitably appears, it will consume every plant.
Always choose robustness over optimization.
World's Only Rational Man 
Robustness is simply optimization for survivability in the face of foreseen and unforeseen adversity.
Marvelously well put.
If optimization were considered as a complex and dynamic balance, rather than as simple “output”, this worry would go away.