Every workplace is different. However, the attitude that comes across in your post is that you have nothing but contempt for your colleagues. They are probably picking this up and don't want to socialise with you!
Did you decide on postgrad study because you wanted life to carry on as it was as an undergrad? Like it or not, you have made a commitment to full time research, which should be viewed as seriously as a full time job. You can still play hard, but you will need a more mature attitude, and to work hard too!