All of us are unique individuals. We all have different processess and ways of thinking and doing things. Of course there may be a certain outline or margins but in order to be productive and bring out the best in everyone, everyone should have some personal space. The freedom of being with your mind and your thoughts can be vital in creating new ideas and can bring out the best in us.
Of course group discussions are also very important but most people don't seem to emphasise on the much needed personal space.