UI design obsession hit as hard as software design obsession, both are equally valid and should be respected. In others words if a designer tell you to move a button 3px to the left, then you should take in consideration his gust and ask them politely why they should. The same could apply if a more experience college tell you that this method don't belong to that class or that function is doing too much. Just respect each other and be on peace for the sake of the project.