There are some jokes which are funny from outside, in fact sometime really hurts. Anyway the relationship is very close between people. You'd better not use these negative and bad words. Can not you don't have to, such as the words: fat, ugly and sick.
Sometimes you may be not intentional. But you can't assure others care. In our life, many people meet this cause, that is that you just make a kidding to him, but he is really angry or believe it is true. In this cause, the between your vibe will become embarrassing immediately, so, there are many books in market which teached people how to talk , behavor and mak friend , could needed by readers more and more .
If you are a child and talk wrong, people will forgive you. But if you as a adult like that, others will think you are a person whith IE or QE low.
What most worried in the life that you hurt someone but cant know it. Have made a very good point: Detail beats love, I'd like to say , somtimes detail will beat a man.
