Personality influences

A couple weeks back NPR’s All Things Considered had an interesting story on a documentary about a man with amnesia.
Unknown White Male tells the story of the man dealing with his lost memory.
The premise of the story is that a man has lost all his memory and can’t recollect any thing about himself, including his personality.
The documentary tells his story.
But the NPR reviewer said the movie begs the question, “Do we learn our personality or is it given at birth and ingrained for life?”
In other words, how much of our surroundings and the people we’re with impact our personality.
According to the report, the man who’s lost his memory is just a shell of his former self.
He’s a different man to all his old friends and family.
Can he regain his personality, or will he become an entirely new man as he re-learns his life, family, friends and surroundings?
I constantly see myself doing things that my father does. Possibly, that could be genetic, but it could also be all the time I’ve spent with him.
I see myself doing things my friends do as well. That’s not at all likely to be genetic.
So, how would your personality differ if you were raised in another family, another neighborhood or maybe another country?