How do your kids do with babysitters, or when it comes time to leave them with a babysitter?

Our 'babysitter' is my 15 year old step-daughter who is great with the littles, but our 4-year old gets super upset when we leave without him. He gets to watch a movie and make homemade popcorn after we leave, which helps, but some nights can be a battle! Our 1-1/2 year old will cry when we leave also, but both are fine shortly after.

How do your little's do?