Why do we say "please" and "thank you"?
Because it is polite.
Why do you drink?
Because you are thirsty.
Why do you laugh?
Because something is funny!
Why do you wear a jacket?
Because you're cold.
Why do you wear sunglasses?
Because it's sunny.
Why do you wash your hands?
Because they are dirty.
Why do you sleep?
Because you feel tired.
Why do you eat food?
Because you are hungry.