Mixed feelings

How should a good reference librarian feel when the student worker calls him/her for help in the break room at lunch or on an evening/weekend when she/he is not scheduled to work but is in his/her office? I suppose an excellent one is delighted. When people actually ask for help, reference is my favorite part of being a librarian. I am very happy to help when called during the day, even if I'm not the person on call. But lately I have been working later in the evenings and coming in on weekends to try to catch up on all of my projects without the usual disruptions, and I am being called to come out for not only reference help, but to un-jam printers and figure out computer questions as well. I'm only mildly and temporarily annoyed with the requests for reference help, I am less gracious for technical problems.

Should I feel guilty that this annoys me? Does it make me less than a good reference librarian?