Celestia likes her routine. Tax reforms, grants, laws and construction projects are all a princess needs to be content. It's just her luck that for Pinkie Pie, "content" is not nearly enough.
During the most violent storms, Pinkie runs outside and sits on the tallest hill in Ponyville. Everyone says she's "just being Pinkie". But she knows that by showing love for the storms, she shows love for the pony who makes them.