The environment we grew up in have a huge influence in who we become. Children imitate and hence the people around them will affect how they behave. For example, children who grow up with people who are polite tend to be polite themselves, and children who grow up in gang-filled cities or neighbourhoods tend to end up joining a gang or adopting more aggressive behaviours.
Culture plays a huge role in our beliefs and values. For example, if we live in a society that values collectivism, we may strongly believe in using our lives for the good of others. In contrast, living in a society that values individualism may encourage us to have higher levels of confidence and self-esteem.
If you want to get into the theory and philosophy, Urie Bronfenbrenner is a psychologist who came up with the ecological systems theory. In it, it describes how our environment and the relationships between these environment (including people) will greatly influence our life.
