The phrase "customer service" has different meanings and initiates different responses and feelings from one person to the next, so it is interesting to see the variable opinions listed here about "Is customer service a nurse's responsibility?"
When I think of "customer service", I think of the following phrase: "DO UNTO OTHERS AS YOU WOULD HAVE OTHERS DO UNTO YOU." Therefore, no matter what I am doing, or where I am doing it, or who I am doing it for, I always try to follow the above mentioned "Golden Rule". I always remember what it was like when I was a patient when I'm taking care of a patient.
I remember interviewing for a job at a military hospital one year where the interviewing panel asked me the following question: How differently would I treat a high ranking soldier versus a soldier who was of a low rank (general versus private would be one scenario). My response was this: I would treat them equally because every patient I care for is given VIP treatment by me because that is the way I believe people should treat one another. Did I get that job? Uhhh...NO!!!

What I was suppose to say was that I would basically "kiss butt" to please the high ranking soldier which to them would indicate that high ranking soldier as being "more important" than a soldier of low rank. Huh! Not in my book they aren't! A Private is the first to die on the front line of a war, not a General, so why is the Private's life of less importance to the hospital over the life of a General? Their expectations of their nurses were NOT humane, in my personal opinion. Every person deserves the right to be treated important!
Guess I gave them the "wrong answer", huh?

Whatever! The answer I gave them was the "correct answer" for the way I try to live my life.
Where should nurses draw the line when it comes to customer service? When we notice that our patients are deliberately abusing nurses just because they think they can get away with it. This is when the nurse should politely, but firmly, let the overbearing abusive patient know that the nurses are not there to service their every indulgence unless what they ask for is for their health and well being in getting well enough to go home.