I am not convinced that an experience such as flying as a PPL would have any lasting effect on ones persona. Depending on ones basic personality though, all experiences can have a positive or negative effect.
What intrigues me more is how some pilots seem to change dramatically as soon as they get near an aeroplane. I know a few basically nice people who become boorish and dominating with a tendency to panic. Others who suddenly change from a quiet, uncertain individual to a positive and relaxed pilot who makes his passengers feel safe.
This type of personality change is even more prevalent amongst yachsmen, some of whom can turn into a tyrant as soon as they board their boat. I worked with one individual who was undisciplined and unreliable until he was on his boat. Then he became disciplined and the best seaman I have ever sailed with.
Perhaps we all spend a lot of our time acting anyway.