Some advice to people that receive straight-forward feedback: If your manager has stated things in factual, logical and respectful manner, with no sense of passive aggressive tone, confront it - I think of feedback, especially difficult digest ones to be very motivating. If your manager has misevaluated still after introspection, tell him exactly how you thought about it and how it is not quite correct due the reasons you shall state. Keep a level of professionalism for each other and smile.