How do you deal with Critics?

I never reply back and that I think is my weakness.Sometimes I take criticsm constructively and sometimes I feel the people who are criticising or guiding you should first look into what they have done in their lifetimes and then they should expect from others.Iam a deep thinker and a shy person so most of the times if anyone comments on any thing I just smile back which I guess may be my weakness according to others but is my biggest strength because by keeping calm you have avoided any hot discussion and your purpose gets served as you do not have to fight automatically person comes to know that you are not happy with his words.After marriage I have become a little bit of bold person.If I do not agree with someone I sometimes reply them but yes till now I havent come across any big criticism and with my patience and maturity I manage small criticsms well..