I found my mothers group was not too bad till a new mum joint the group when the bubs were 6 months. The group started to polarise with her and became less tolerant of different parenting choices. Before her we all got on, were supportive of each other and most of us had made at least one good friend out of the group. Wish I had left before she had joint, as it just got plain nasty after her. Such a shame as it had such a great start. Amazing how 1 strong personality can change things.