Night time questions

One night Daniel couldn't go to sleep.

"Mummy, why do dogs bark at night?"
"I can't hear any ..."

"Mummy, why do dogs NOT bark at night?"
"I don't know. Let's just sleep."

"Mummy, I need water.
"OK."

A moment later, Daniel accidentally drops the cup on me, also flooding the sheets and his pyjama top in the process. After changing the sheets and his top, he closes his eyes again.

"Mummy, I still can't sleep. It's because my pyjama bottom... it's red and it doesn't match the top."
"OK. I'll get you a red top.

"Mummy, my back is itchy."
"Never mind that. Just go to sleep. If you sleep, you won't feel it."

A few minutes later, out of the blue:

"Mummy, when I was in your tummy, did an angel come and tell you?"
"No."
"So how did you know?"
"...."

Then again:

"Mummy, I don't want to be a person."
"What do you want to be then?
"Grass."
"Really? But what if a bunny hops along and eats you ..."
"Hmm. I want to be a double decker bus then."
"But why don't you want to be a person?
"I don't want to get artificial teeth when I grow old."