An individual is the product of his/her culture.
What language he use, what dress he wear, what food he consume, how he behave with others. In short, whatever we do, we do it cuz our culture wants us to do it in that way.
And if we try to do different, we become outcast and other ppl. avoid us, so in a way they are putting pressure on us to behave according to the culture of the society.