Look before ya leap...

A store manager overheard a clerk saying to a customer, "No, ma'am, we haven't had any for some weeks now, and it doesn't look as if we'll be getting any soon."
Alarmed by what was being said, the manager rushed over to the customer who was walking out the door and said, "That isn't true, ma'am. Of course, we'll have some soon. In fact, we placed an order for it a couple of weeks ago."
Then the manager drew the clerk aside and growled,
"Never, never, never, never say we don't have something. If we don't have it, say we ordered it and it's on its way.
Now, what was it she wanted?"
The clerk smiled and said...
"Rain..."