They are the reason the library exists. Judgement calls are to be made in the patron's favor. If a mistake is made, it should always be to the patron's advantage. If a staff member is unable to comply with a request the patron will be offered an alternative. Staff members are familiar with library policies and are able to articulate them and to explain the rationale behind them.
Body language conveys attitude just as the tone of voice and choice of words affect a message.
A friendly helpful demeanor usually ensures a positive experience even when the message conveyed is not a pleasant one. Staff members are expected to act in a friendly, helpful manner which will ensure that the patron will walk away feeling that their experience with the library has been a positive one. Each staff member, while at work, is a representative of the library. The impression made on the patron profoundly affects the library's image and on-going support. The needs and requests of library patrons must always be taken seriously and treated with respect.