Trust and Reliability. We can all agree these words have immense value. They're used to emphasize integrity. They extend a promise of accountability to those who rely upon us whenever and wherever we're needed. These words should govern the culture, ethics and vision for your help desk.
All help desks should all stand by these values, to be trusted and reliable. In IT, if customers can get their problems resolved when they contact support they will be more willing to report them, which leads to a better understanding of what challenges the business is facing and how IT can resolve them. All derived from those two words.