I enjoy cooking. As a cook it is always nice to hear compliments from the diners, but if something doesn't work it is equally important for me to hear that as well. The only way we can better ourselves (or our culinary skills) is through feedback about what works and what doesn't.
Having said that, it is also important to remember that the manner of presenting comments is important. If I am invited to a dinner party and I do not like what is served, I am not going to announce to everyone at the table that the food is terrible. If the hostess asks me my opinion, I will be honest in a polite way. Communication is a social skill that aims at building understanding between people. If we are not honest then we destroy the basis for that understanding, but if we embarrass or offend the person with whom we are communicating then we also destroy the basis for common understanding.