That is a sort of philosophical question, as for me. For people also define culture a lot. Still, that is true, the culture you were born in defines your personality, as it forms your character and manners a lot.
The writer W. Somerset Maugham said about culture building a person:
“It is very difficult to know people. For men and women are not only themselves, they are also the region in which they are born, the city apartment or the form in which they learned to walk, the games they played as children, the old wives’ tales they overheard, the food they ate, the schools they attended, the sports they followed, the poets they read, the God they believed in. You can know them only if you are them.”
That is so indeed. The environment we live in, nationality we hold, our race, religion, and beliefs - all of this influences what kind of people we are, how we behave.
We can clearly see the difference between people from Europe, America and Japan, once we see them in one place. Practically everything they do is defined by their culture.