What Do You Want Your Customers To Say?
You're in a restaurant. You've been served and are eating your meal. Your table is then approached by a waiter/waitress and you can be asked one of two questions.
1) Is everything OK?
2) Is there anything else I can help you with?
Unless you're particularly belligerent or annoyed, your response to the first will probably be a polite "yes, thank you" regardless of the situation. You'll feel faintly patronised and the establishment will learn nothing about how to improve their service nor understand why you don't return.
Always ask questions that give you meaningful answers. You may not always like them, but it's far preferable to sticking your head on the sand.