Why?

"Why is the clouds gray and not white?"
"Sometimes they get so big that they become darker."
"Why?"
"Because they are so thick that it is harder for the sun to pass through."
"Why?"
"Because the cloud is thick with water vapor. There is a storm coming, so the cloud is getting bigger and bigger. The sun can't go through all of the that thick water vapor, so it makes the cloud look darker"
"Why?"
"Because (followed by a lengthy explanation about thermodynamics)..."
"Why?"

At this point, the person answering gives me a look of desperation, "Does she ever stop saying 'why'?" "Nope."

I think it's always kind of funny when someone who has never had a 3 year old talks to my daughter. They keep answering those adorable "why's" over and over and over and over... Those who have had a 3 year old know the answer: You just stop answering.