Everyone knows the expression but not many people act on it. To start with, you may be the boss of a large organization, you may be the project manager, you may be the one doing the actual communications with clients and potential clients. But what you really are is a shoe. And in order for anyone to buy a shoe it needs to fit.
If the shoe doesn't fit or if it leaves a bad impression or if there's no guarantee or if you just don't like the salesman - you don't buy the shoe and you go to another shop.
Remember, you are the shoe. And you need to fit.
This means that your clients and employees (hopefully not) may be stupid, they may be rude, they may have problems that do not exist, but you can never ever answer the same way. You always need to be politically correct, always friendly, and always timely, always leave the impression you want to help solve the problems (and you actually do want to do it, otherwise, change the job). Client is the King and you are the shoe. Remember that. And the King is always right.
You know what else? The King wants to be able to do everything the way he wants to do it. Yes, I repeat the words here, but the King wants to do what he wants to do. Let him do it. You are the shoe, your business is the shoe and if the client wants to put black pasta on you, you welcome it. Let your client create your product, let them customize it. And if you're in internet business, that's not so hard to do. Let them play with your product. Now everyone has their own different, personalized product, product they like. Product that is so unique only a King could have. Now the client is happy and so are you.