For all we know water could be having a furious debate with itself -

Shall we flow uphill?
Why do we want to go up the hill? Its easier if we go the other way?

Ah yes but then we'll never know what is on the other side of the hill?
What about the laws of gravity?
I refuse to be screwed about Gravity.... Why should we be constrained by the Gravity family. when you're lost in the rain in Juarez, negativity might pull us through...