The phrase "optimise globally, not locally" is used often. So is the phrase "sleeping like a baby". As with the second phrase, the first one isn't appreciated fully.
"Sleeping like a baby" means to wake up screaming every hour requiring a nappy change. Coincidentally, a local optimisation in spite of the global need has exactly the same effect.
Edited slides for online viewing is available here: http://www.slideshare.net/danieroux/danieroux-agileafrica2013onlineslides