No problem is a big problem, So we want to actually encourage conflict in the sense of encouraging openness about disagreement, which in turn suggests that it is essential that we are prepared to resolve conflict - http://jchyip.blogspot.com/2011/10/conflict-will-and-should-occur-be.html 

Should DEV work in prod? - http://swreflections.blogspot.hk/2014/01/developers-working-in-production-of.html