When kids get a chance to pick their partners they will become more caring and more serious. They will develop a sense of positive responsibility among students. When students get a chance to pick their own partners they'll take up the decision more wisely and they'll become more responsible in life too. If kids pick their own partners they'll know that they are choosing the right one with whom they can spend the rest of their lives. So if kids are given a chance to choose their own partners they'll become more active and serious in life.
Despite teachers, trying to help kids fit in there are always kids who don't have many friends in that particular class. This causes exclusion and that is a problem that we can fix if we just have teachers pick students partners. Its not always the kids fault that they don't fit in.