As humans, we decide what is acceptable by soaking up the influence of our surroundings. As such, most anyone you come into close contact with, for example, your parents, professors, and close friends exert a large quantity of influence over you and your decisions; their thoughts, ideas and opinions on things have an impact on what we believe is possible in our lives.
On a positive note, your inner circle will exude a feeling of belonging and well being. But on the other side of the coin, there is resistance and even envy in some cases. There is a well-known experiment involving monkeys that illustrates this idea powerfully.