I like the way you talk about both compliments and criticism because both are necessary. Both of these can backfire if not handled properly. One thing that helps is to be specific. In each aspect, whether a compliment or a criticism, pointing to the reason for the comment goes a long way in helping the receiver understand why it is being given. I've seen people get offended over a compliment such as, "you look nice today".  I guess they immediately think that a compliment like that means they don't look good other days. Culture and personalities all have an affect on perceptions - and it's that perception thing that compliments and  criticisms rise and fall on.