G: Why did Peter lose his jacket?

Me: Because his buttons were caught.

G: Why were his buttons caught?

Me: Because they were stuck in the gooseberry net.

G: Why was he stuck in the gooseberry net?

Me: Because Mr. MacGregor was chasing him.

G: Why was Mr. MacGregor chasing him?

Me: … because roughly 13 billion years ago, the Big Bang happened, and therefore eventually Mr. MacGregor decided to chase Peter.

G: … what is the Big Bang?

Me: It was a giant explosion that created the universe as we know it.

G: <slaps his own knee as hard he can> — That was a Big Bang!