In the first season of Mad Men, it is revealed that Don Draper was born Richard Whitman, but stole the identity "Don Draper" from a fellow soldier who died in Korea. The other soldier's body was not recognizable, so Whitman switched dog-tags with the dead man, and acted as if he was Don Draper from then on.
What was the motive for switching identities?
Was it just to cause his family to think he was dead? I understand he was ashamed of his roots, but it seems like he could just end contact and never go back. Why risk all of the hassle from stealing another guy's identity?
Or, was there something about assuming the higher rank of the other soldier, perhaps to go home from the war? I believe there was an episode where Don justified the identity theft by saying something like "I had to get out of there", but even that comment seems ambiguous.