Stan: Why don't squirrels cross the road?
Mum: Because they're not very good at it and they get squished.
Stan: Why aren't they very good at it?
Mum: Because everybody is different. Some animals are good at some things and some animals are rubbish at other things. What are you good at?
Stan: Ummmm, squashing berries.
Mum: Ok, what are you rubbish at?
Stan: Cutting dogs in half (big pause) Muuuuuum, what's inside a dog?