Criticism by definition can be the expression of disapproval or the analysis and judgment of someone based on merit, etc., but criticism in itself, although sometimes overly critical, can be a helpful tool in workplaces, schools, real life situations, and many other outlets because not only does criticism give you a look into what you could be doing to improve your own personal outlets, but it can possibly help to improve your self confidence.
From what I've found, one of life's biggest lessons is learning how to deal with criticism, and also learning that not everyone deals with criticism in the same ways. Some people get a bit offended when they're criticized, some people get angry and fire back at those who are criticizing, and some take it constructively and not as rude, but as helpful to improve themselves and whatever they may be doing.
In searching for what others think of criticism, I have come to the conclusion that everyone feels differently about how criticism, self or otherwise, impacts the person receiving the criticism. In asking other people what they think, I have found that some people really live for criticism, because without it, improvisation has to come on one's own. I've found that some people are very self-critical, myself included and that, that can be very hard on self-esteem. For example, someone might be critical of their appearance or their body weight, even though others don't see those things wrong or see them as perfect the way they are. I've always been one to overly criticize myself in a negative way with aspects like school and my own qualities. Recently I've been trying to do things for myself, like pat myself on the back when I feel I've done a good job at something, but also to constructively criticize myself, as many people should also be doing.
I've grown up learning that criticism is a necessity in life because when you are criticized, it means you must be on the right track. Most recently, I was very rudely criticized in front of a group of people by a person who had never met me before in their life, but everyone can be someone else's critic in today's society. Although I was very upset at the approach of the criticism towards me, and I was angry at the person for criticizing me just because they felt it was appropriate, I realize now that I can only learn from this experience. I will admit that after this happened, I was feeling the need to criticize myself and reevaluate what I was doing, but I now see that everyone is their own worst critic and we all need to take a step back from the self criticism that's hurting us and take a step in the direct of being our own biggest fans. Because in a world like this, a world full of critics, we need the positivity of being a fan and give ourselves the constructive criticism we need to help us improve the way we live our lives.