Although Nina DOES have her tantrums, Abi can see that she is a sensible sister. A very orderly one that is, so much so that whenever Myra threw something out, Nina would be mad trying to keep things in order.
Another thing is that Nina is possessive. Any of her belongings, can be used by Myra ONLY at her approval. Most of the time, she'd reposes what ever it is that's in Myra's hands.
And during those times, I just wonder in amazement looking at these beautiful creatures...