Why do people get their "feelings" hurt?

Since I do not have true knowledge about people I will set myself as reference. I am not sociopathic so I do feel, though I try to understand rather than repress it. Because of it I can filter the content of my mind and choose to be indifferent of whatever is not useful. I guess some people do not do it, so they are subject to instinctive emotional responses. They get offended, get aroused, get sad, get happy... instinctively i.e. they do not 'filter' the content of their feelings. Since you do not have any emotional response it is really difficult to explain what is like to feel, yet I can give a more simple objective explanation: it is like a machine repeating what it was meant to do, it does not analyze it just do it.