Some guys don't mind talking about their combat experience. In fact, quite a few vets have written books about their tour of duties in Vietnam.
I remember seeing a documentary about a Vietnam Vet who was walking along a trail, alone, and spotting a lone VC. They startled each other, then the U.S. soldier shot and killed the VC. He walked over to him, searched his body, and found a picture of the VC with his wife and kid. The U.S. soldier put that picture in his wallet and carried it with him for 25 years. Finally he decided to get rid of the picture so he flew back to Vietnam with his family, searched for the woman and girl in the picture, and returned it to them.