Throughout life, we meet many people. Regardless of the amount of time, we spend together these people undoubtedly will have some kind of effect on us as an individual. In the scenario of friendships, we become more empathic about their beliefs or norms.
No matter how big or small these traits maybe over time it starts to change how we think and act. Individuality is what we are born with and relationships with others build on top of our individuality.