The first reason may be you themselves. Think maybe it's not to offend you, but you're just so touchy person who takes everything too close to heart? If so, the first thing is to work on yourself than to be offended on other people.
The second reason may be the well-known "vampirism". This is when people just clings to you in detail, in order to receive for your expense of energy. Such people often unremarkable, so they attract attention only in this way. For example, they may be rude to you for no reason. You should not respond to such people. Best preignite such a person. You also only this will be better.
Also cause of offense may be simply that we don't know how to communicate and listen to the other person. Often because of this and hurt each other people of the opposite sex, for example, a husband and wife.
You know what the heat of passion? It is a violent psychological shock, because of which the person is not able to control their emotions. Agree, because not everyone is able to answer for themselves and for their actions in a fit of anger and despair. That is why they hurt others because they did not control yourself in the moment.
Well, the last cause is the lack of manners. If a person was raised in a very rough situation, he, accordingly, will behave in relation to others. And for sure, not because he wants to hurt you, but simply differently he can not communicate. If this is the case, then the problem is just, that he, in fact, can easily solve. This is only want to. Good luck!