Similar here when picking up youngest (2 and a half) GD from nursery- she runs round shouting 'Grandma, my Grandma'- and only after a full circuit will she start to get ready for home. Oldest GD is 9 next month and knows her own mind! When she and I went to see Mamma Mia 2 in the summer I was told in no uncertain terms 'dont sing Grandma!'. We went to a musicals type singalong at our local theatre about a month later and the audience were being encouraged to join in. GD gave me a look, then said 'Its Ok to sing Grandma, but PLEASE dont get up and dance!'. 
what is this behavior called does it have a name?
Angela Rayner cleared by HMRC. What a coincidence!
