Restraunts/ Coffee shops.

Why dont some of them have menu's to inform you of what they do. I mean, would it be too much trouble to put a sign up with what food they do. Are we meant to be psychic? and what about people with food allergies? if the place doesn't have a menu then you have to be told what there is, its annoying to have to stop the assistant every two minutes to ask whats in the food. By the way i dont have food allergies but a friend of mine does and she has this problem a lot. Rant over lol.