It is amazing that some of the most homely, hooky, and utterly corny mission statements in corporate America having to do with customer service are also the most effective, but it's true as many a HBR (Harvard Business Review) article has noted. Do you know why this is? It's because they are so easy to understand that everyone can grasp the concept, the employees get it, and they carry out the mission because that's what's required, and what's expected.
They have absolute buy-in, and if you do it right it becomes a group passion and it is amazing the outflow of energy which is felt by the customer as the employees try to please them and explain how great the company is, and how much they care, and they mean it, because they really do. The customers feel this, and it adds to the ambience and the customer experience. It works. And since it works you should be doing this in your company, big or small it doesn't matter.