"NO" is not always "NO"

You’re smart.  You’re talented.  You’re educated. Data analysis is your best friend.  Sometimes your data will lead to inescapable conclusions… and your boss will not agree.  (Even if you run your own business you still have a boss:  Your customers.)  Why won’t your boss agree?  Sometimes decisions are based on more than analysis, logic, and reasoning because decisions must eventually be carried out by people — people with a wide range of skills and motivations and emotions and agendas.  Leadership should be data driven, but great leadership is also messy and sometimes counter-intuitive.  If your boss doesn’t agree with you then absolutely ask why, but ask in order to learn and not just to defend your own position.  You know things your boss doesn’t know, and he or she knows things you don’t know — at least not yet. You only learn from another person’s experience when you listen.

http://m.bnet.com/blog/small-biz-advice/5-great-leadership-lessons-you-dont-want-to-learn-the-hard-way/1970?tag=content;drawer-container