IT has to create value for the business by its services. This main principle has to be always kept in mind and focus on. An IT service promotes or allows the customer to reach business goals without undertaking special costs and risks.
In IT services both WHAT and HOW are crucial. What means "fit for purpose". The service has to fullfill the business requirements obviously, but it's not enough. How means "fitness for use". Using the service has to be easy, convenient, fast and smooth. Either is missing, the customer will be disappointed.