OK, but what generates high customer expectations in the first place? Perceptions of the business are important and these can be generated in many ways. Reputation, word of mouth, knowledge of satsifactory delivery, even good advertising and publicity management.
You hint at this in your response, but flexibility and willingness to compromise are also important.
Managing the communication is also important, listening to what the customer is saying and trying to answer that, not reading from a pre-determined script, being customer focussed in the interaction, make them feel they have a champion in the organisation, without giving away the store.....
Do those help?