Both nature and environment affect one's personality. But if I have had to choose just one of them between them, I would say the latter. The reason why some people usually have similar personality with their parents is that that is what we have looked in the childhood they see and imitate from them. People are born with only potentials but the real personality is determined by what we see everyday.

In conclusion, I believe the that personality is developed rather than inherited.

I like your idea!