See, I'm just the opposite!
I'm not convinced I want to be a MOTHER, but my god, do I love other people's kids.
I love to play with them, and read to them, and make cookies with them, and go to Disneyland with them, and I LOVE to give them BACK to their parents at the end of the day or the weekend!
I bet I know what made poor little Megan cry. Raeanne got to have her nap in bed. Megan was being exiled to the couch. She was feeling unwanted, jealous and maybe a little put upon.
In case you ever have Megan again, try this: instead of putting Raeanne in her bed, put them BOTH in a big nest on the floor--big soft blankets and a bunch of pillows. Lay down on one side of the nest with them and read a book with them till they fall asleep. If the dogs are interested in joining in, it's even better.
This nesting works because it's a treat for them both. And if you only let Raeanne 'nest' when she has a playmate over, it will stay a treat and will work for a long time. I have a friend whose 9 year old is FAR beyond the nap stage, but who will totally sack out in a nest on the floor with his younger brother and sister in the middle of my living room!