Why acted like this?

So I have a friend who are quite a typical criticism and sarcasm. Sometimes it's good to do so for the sake of  justice but this no. Come to think about it, if you have a friend who always hang out together, willing to give you a lift, even celebrate your birthday... how can you sometimes never put yourself in their shoes and don't mind to make people feel awkward after throwing your words out...this act I have been seeing since secondary school but surprisingly at this age. Sometimes we talk, we share our thought but never step on people...some people may argue that good friends are meant to tease each other, I tell you this apply when we mutually feel the fun but if in a negative way, the people will just get pissed off by nature. I don't know whether are you going to ponder about this or just leave it and carry on with your life by your current nature..maturity (or social skill in this context) is gain through experience, trial and error, and comments about you from the surrounding. I can just say that this is my little piece of comment, it's bugging me a little or else I won't do so... Therefore, what are you going to do is all leave it to yourself... PEACE !!