There is a difference in a real "WOW" and just the wow-effect.
While it may be tempting to quickly tell a client or customer "sure, we can do that" because you want to get the business, or to say "I am not sure if we can do that" because you want to surprise the client or customer when you do get "that" done, are you really being a person who WOWs, or a person of woes who is going for the wow-effect?
Those who WOW go above and beyond, surely, and it is done to care for a client or customer, patient or another person. Wanting to wow is terrific, ensuring a wow by setting something up without an appropriate expectation (what I call the "wow-effect") is setting you, and your clients/customers/patients up for woes eventually.
Appropriately promise and appropriately deliver (Instead of under-promise and over-deliver, also know as "sandbagging" or over-promise and under-deliver, AKA "here comes the excuse") so that your WOW moments come in things that are truly special extras, and not just based on timing that you manipulated or inflated in order to have the wow-effect!