Thing is, over-optimizing is not optimizing. "No plan survives contact with reality", as it is said. Optimal strategies in games, for instance, include lots of adaptive branches to deal with the suboptimal reality of what actually happens - otherwise the plan is really fragile.

(Having said that, restarting a game over and over in order to force your one perfect linear optimal plan to eventually work out can be lots of fun. But this is not an option in real life.)

While I'm on the cheesy aphorisms, I'll throw in "life is what happens while you're busy making other plans". But that one's too pragmatic, I think. It's not as if we have zero control. Maybe a more accurate statement would be "life is what happens while you're busy making loosely similar plans".