Why does it all hit the fan when Dad leaves?

What is it about the presence of "Dad" in the home that keeps my girls a wee bit better behaved? Last night Henry came home for dinner before having to return to church for a rehearsal. We had a lovely hour or so together as a family. Then it was time for Henry to leave. We all received our goodbye kisses, and he was gone. I swear, within 45 seconds of the garage door closing, it all hit the fan. Amanda, who was nothing but sheer contentment while Henry was home, began moaning, and then crying about her tummy hurting. This, of course, was AFTER I told her to get into the bathtub. Then Megan, who was the last one sitting at the table, because she had chosen to goof-off during dinner instead of eat, decided to run to her room while my back was turned washing the dishes, and retrieve a Hippity-Hop (big round ball with a handle that you bounce around on) and put it on her chair to sit on while she finished her meal. Well, as soon as I saw this, I told her there was no way she was going to sit on that thing while she ate her dinner. So she proceeded to stand on the chair, pick up the Hippity Hop and place it (not on the ground, mind you) ON THE TABLE where it rolled and knocked over a very tall glass of water!! All the while Amanda is crying in the background about her tummy ache. Are you kidding me?!?!?

So naturally I called Henry, not to blame him, but rather to let him know just how well things had gone since he left 3 minutes prior.