Seth Godin has a fantastic post where he mentions the fact that how precise language can change an organization. Here's his take:
Sometimes, precise language can change an organization.
How many times has a broker, or a clerk or a salesperson or some other intermediary (who was just a moment ago being quite helpful) turned to you and said, "I'm sorry, we can't do that."
We can't comp your room.
We can't let you use the showers.
We can't reduce the fee on a very large transaction.
We can't take this car in trade.
We can't give you a raise.
In fact, the correct contraction in each case is "won't."
And once you say "won't" you realize exactly what you're doing.
You're telling a prospect (the most important person in your life, at least in this moment) that your organization doesn't want to accomodate them. Want being the key word.
You're telling a repeat customer (the person most likely to start spreading good word about you) that your organization doesn't want to create an impression worth repeating.