Priority moments in customer experience

When is it most important to get my customer experience right?  To exceed my expectations as a customer and wow me at that critical moment so I not only become a return customer but a champion of the brand?  At point of sale? At point of complaint should there be a problem?  Browsing before I have decided I want to purchase your goods? Key is to consider at each stage where the experience could be strengthened and deliver that added ingredient. If my product is being delivered I see the delivery agent as an extension of your brand so flexibility and professional service are essential. Wherever the customer touch point is it is a priority and any dip in standards will wipe out all the other good that may have been achieved. Make it count from the first moment to the last and make me into a sales person for you.