Always give the customer a choice. If one of the choices they are given is no, that’s the one they will likely choose. Therefore always give them a choice that will result in business for you, whichever option they choose, i.e. would you like the red one or the blue one? Would you like us to visit on Wednesday or would the week after be better? Never say anything stupid like, “Can I help you?” or “Would you like it?” because the choice they make will almost always be no.