Free writing--The art of "speak"

Recently, someone give me an advice that he tell me not to speak sarcastically. He means that I usually use unsuitbale words to discribe something.
He give me an example that one day someone had a haircut and everybody all said "It's good look on you". One the contrary, I wouldn't give him admiration positive.
I acknowlegde that sometimes I take a dig at others, then I felt regretful about that. but I am not deliberate to do that.
I think I should learn how to speak with the correct word, and try to presuppose how come when I speak something.
Maybe I should to be the guy who with a heart of gold, and give more praise for everything.
"Oh~Fantanstic!!"