"Why?"

We've entered the "Why" phase.  About a month ago Owen started asking, "Why".  Chase has caught on and now asks it more than Owen.  When the sun was setting earlier in the day we would be driving home from work/daycare.  The boys would comment that the sun was going down and then, "Why?" came from Owen in the backseat.  Every day I would tell them why, telling them about the rotation of the earth and the tilt, etc.  As soon as I would get done telling them this Owen would ask, "Why?" again.  So I would say, "It just does every day."  This satisfied their curiosity and they stopped asking why.  However, it was the same the next day.  It's pretty funny most of the time.  Here are some examples of what they are asking "why" about.

There's a cow.  "Why?"
Your shirt is blue.  "Why?"
Who wants cookies?  "Why?"
Let's eat dinner!  "Why?"
It's time to go to bed.  "Why?"
It's snowing out.  "Why?"
Mommy is tired.  "Why?"  (why do you think is what I want to say.)
It's time to go to church. "Why?"
Daddy washed his car.  "Why?"
Look, the kids are outside playing. "Why?"

and the list goes on.  It's so sweet and innocent and they are learning, so I cherish it.