Constructive Criticism

Is there really such a thing as constructive criticism ? To me, the word criticism sends out negative vibes. When someone criticizes what you are doing, they are really just complaining about it. What you are doing doesn't meet their standards.  Why do people think that their standards have to be yours? What is good for me does not have to be good for you. Nor does it have to please you. When I teach my workshop on communication we discuss how to get our point across in the most positive and effective manner. I use the term "don't complain, just explain". Instead of criticizing someone else's actions just explain how you do it and let them adjust their way if they want to. If not, you need to adjust you attitude towards it.