I feel that it can be much easier to communicate with an audience who doesn't know me. I sometimes feel more free just to say exactly how I feel. With people who know me I feel they might judge me more because they know my past and tendancies and I almost feel an obligation to tell them stuff that lines up with what I think they think of me. Does that make any sense? It does to me. If I am talking with a counselor I feel very free to say anything and everything. I know they are there to help with no other agenda at all, and they are not suppose to judge either. Something someone who knows you might do more readily without even thinking about it.
I know that a lot of people don't feel the same way. They really don't like strangers to know a lot about them. (a personal file) I can totally understand why someone might not want to open up to someone they don't know or trust. So I guess it is the counsellors job to build that trust and show that they care and are there to help without bias or judgement. A tough job I would presume.