My five year old son did a cute one the other day.
His Grandma picked him up from school, with the plan that they'd get the bus home here (only about 5 minutes).
They waited, and waited, but no bus turned up - so they walked up instead.
Whilst we were having a cup of tea, about 3 buses went past.
Anyway, he was talking about it, as he knew hat Grandma was sad / annoyed / disappointed with the buses.
He said to me "I was sad in my brain, but I showed that I was happy on my face".