Slippers here in the winter time, as there's no carpet in our home.

In the spring/summer, I just ask for good shoes. I keep a pair of rain boots here for each child. If we're playing outside with water-play, we're usually bare-foot, but otherwise they have to have something on their feet!

I usually tell parents crocs if they ask what I prefer. As long as it's not flip flops or cheap-y shoes that give blisters.