how do you respond to criticism?

If someone is being critical of me and it is mean-spirited, I tend to smile and ignore them. I've heard from people who were around when I walked off, and they said it just made the person incredibly mad because I didn't make a fool of myself by responding to them. Usually the person wants to make you feel bad about yourself because they have no self-esteem, or they think they will look cool in front of other people. I just think by experience and observation that it really makes the critical person look plain 'ol pathetic. Now if it is just you and the critical person I don't have a problem with responding to them with concise and articulate responses. It seems to make the other person really angry that they can't make you as mad as they are (even if you are inside). Constructive criticism is telling someone something that will ultimately better that person. Criticism is a complaint you have against another that will do no good for them to know, but you have to tell them to make yourself feel better. Just my opinion!