its terribly hard to walk right in a middle of a group session already going on. People r already comfortable with each other. Things r set into a routine, and u mess up that routine by not knowing it. To be honest some groups can be very possessive of their group and will look at u as an outsidier. I came late in a group and it was hard to fit in. If u cant catch up quickly and the therapist is horrible, u should see if u can come back when the group restarts.