read op so more specific advice. Often if you don't speak to your coworkers the others can feel it implies that you do not consider them worth speaking to/getting to know. This is seen as not caring about them as human beings because of you view yourself as better than them. Hands in pockets is not necessarily a sign of that on its own, but in conjunction with other signals can be taken as disdain/lack of interest. You may wish to evaluate when you are getting this feedback (perhaps there are other things going on that could explain it just as well that the other person would not be aware of/that you do not feel comfortable revealing). If this is your attitude, then perhaps it is time to grow.