Best seat in the house

I shall write this as if I was S1 doing it according to what I think must be going on in his head:

Hmmmm, I think I'll go into the kitchen. I feel like sitting down. Hmmm, mom is sitting in a chair. Silly mom, that doesn't look too comfortable. I'll pull down my own seat. Oh, it's nice to sit on this oven door and bounce. Good thing it's not hot today. What's the problem mom? Wait, the dishwasher (it's portable) is next to the stove. Ooooh, I bet I can sit on that door too. Let's see. Yes, it does open. I can sit cross-legged on it and see myself in the oven door reflection. Now to pull out these clean wooden spoons and start drumming wherever. Cool. This is definetly the best seat in the house. What's mom's problem?

I have to assume this is what he is thinking, because what else would it be?