Now, there is a difference when people say something, criticism vs. constructive criticism. For starters, let's begin with the basic definition in english so we can all have a common ground and definition of what it means.
Criticism; the act of passing severe judgement; censre; faultfinding
Notice the the word finding in italics? Precisely.
Constructive criticism; criticism or advice that is useful and intended to help or improve something, often with an offer of possible solution.
It's interesting when some people get offended or feel peculiar when I react in a certain way to what they are saying. Believe me, as much as I am a egoistic, 'must-save-face' person, I do know how to take a backseat and listen and own up to things if I have done it wrongly, which don't happen very often. But you get the point.
At the same time, I'm good at smelling sarcasm and negativity, being one good at giving it, that comes naturally. So when I get criticised, it is only a instinct for me to get defensive, or at the least explain to you why whatever happened, occurred. Even a stronger reason as to why I defend myself very strongly, is because it disgusts me how as a person, you painstakingly fish out flaws or shortcomings that I have, and fault it.
You, with malevolence, want to make a comment, so you can bring someone down.
And interestingly, when caught doing that, they pass it off, saying that they are given constructive criticisms/comments. Constructive they say.
Frankly, it's pretty gross I could spit. How insecure, sad, angry are you with your own life, where you have to start pulling people down so that you can elevate yourself up a little bit, giving yourself a crown; that you are all mighty and superior, and you have a picture-perfect life. No one has that.
Now a constructive criticism is different. As seen above, it has the intent to improve something. And how do you know that a constructive criticism is made? When you hear it, you don't feel angry, you feel gutted, definitely a hard pill to swallow, but deep down inside, you know that the person has true intentions for you to improve as a person.
And these people usually take form of friends, true friends, who from time to time, serve as advisors.
I defend myself when I'm get a criticism is because, I know for a fact that the comment given out was with contempt, and that there was nothing positive about it, and was designed to say it just for your own redemption and maybe pride. You see, when a criticism is passed off, humour may come along with it, and people laugh, and for a minute, the arse would feel a gleam, that attention is finally passed to them.
Make better sense of what is said about and to you, and be thankful to those that say things for your benefit, and defend yourself when those with unruly thoughts start to come at you.