Ethics and the crazy patron

A co-worker told me last week that he believed the proportion of patrons we help at our library has shifted perceptibly toward the less-than-stable by a wide margin over the last few years. Since he has been in the field a lot longer than I have, I trust his judgment, which confirms my own feeling that the majority of people I "help" on any given day are using us for purposes other than our stated goals of providing avenues for serious research or entertainment to our communities.
There are three elements to this: 1) These patrons are not getting the help they truly need, which is psychological; 2) It is not always immediately apparent that the person with whom we are engaged is "out where the buses don't run"; and 3) In theory, neither 1) or 2) are supposed to matter to a professional librarian--our ethical code is such that we are supposed to treat every question and every questioner as having equal merit deserving the same considerate response. The problem is that because of our ethics, librarians are duty bound to interact with (apparently) more and more unstable members of our society, both in terms of quantity and quality, and for me, at any rate, that is becoming less and less tolerable. I derive no satisfaction from delivering reference service to some patrons, simply because I know for a fact that they are out of their freaking minds. It's really not all that difficult to tell once we begin our reference interviews, because the nature of their questions becomes demonstrably irrational or nonsensical.
For example, I was once asked to provide the "contact information for japanese jazz." I was told that "years ago, [we] had featured a magazine article about japanese jazz" and that now this patron wanted to contact "japanese jazz." At first I was stumped--what was this person really asking for? Their question, on the surface, makes no sense, right? By training and ethic, librarians are forced to delve under that surface to tease out the "real information need", so I proceeded to ask this patron some questions. Did she need to locate that original magazine article (which would have been difficult enough, considering that at no time in any past did our library "feature" articles/magazines for display purposes or anything else one would associate with that term)? No. Did she want contact information for a particular performer/producer of "japanese jazz"? No. Did she want contact information for a record label known for distributing "japanese jazz"? No. With each question I asked, she was getting audibly more angry with me. (This is a common reaction to reference interviews, in my experience, because the patrons can't seem to understand that since we aren't in their heads, we have to ask these kinds of questions to figure out what the hell they are talking about. The more questions we ask, the worse their reactions become, because they seemingly assume that we are actively trying to keep them away from their goal, even if we reassure them that we are simply trying to ascertain exactly what it is they want.) As she got angrier, I became more defensive and frustrated, because it was dawning on me that she wasn't misspeaking at all, she was simply crazy.
I asked her point blank: "Are you asking me for contact information for the style of music 'japanese jazz'"? Yes! "You want me to get you the address and phone number for a kind of music?" Yes! "You don't want names of people or organizations. Is that right?" Yes! I tried reasoning with her, even in the face of this insanity. "I'm sorry, ma'am, this question makes no sense to me, and I don't believe I can help you. There are organizations and people associated with styles and genres of music, but you cannot contact the music itself." Whereupon she began berating me for my unhelpfulness and bad attitude, because what she needed was so obviously simple: we had featured an article several years ago on "japanese jazz", and she just needed the contact information for it." (As she had told me repeatedly already, of course.) She finally told me to "just type 'japanese jazz producer' on your computer and tell me what you get." (This is a request that immediately causes me frustration and resentment, because the person clearly has absolutely no clue what a computer, or the internet, is. People with this attitude think that the box on the counter is magical, and that all we need to do is type their words exactly as they speak them, and the magic box will deliver them exactly what they need. Any attempt at explanation is met with either disbelief or immediate claims of proud ignorance, combined with the exasperation attendant with my clearly deliberate stonewalling their quest.)
I complied with her demand, and told her that there were over 175,000 results. She demanded, with smug satisfaction that she had defeated my intransigence, that I "read what was on the screen" and "give me the names" even though she had, less than 5 minutes prior, told me that she was most definitely not interested in getting the names of people or musicians associated with "japanese jazz." I told her that what I was seeing were just some random names of musicians from various and sundry websites that may or may not have anything to do with "japanese jazz", but in her triumph all she wanted me to do was give her whatever names came out of the box--even though not one of them had an address or phone number attached to it.
This kind of interaction occurs daily, and I am getting very, very tired of the struggle to maintain any attitude of helpfulness. The impossibility of knowing whether the next phone call or person walking up to the desk will result in a person literally screaming at me or abusing me with disdain, simply because I am doing my job appropriately, has created instead an air of dread surrounding my time on the reference desk. That the odds of this happening are increasing, as confirmed by my coworker's observation, is a depressing and discouraging thought. The other possibility, to which I am hardly unaware, is that I am simply a bad librarian, and am causing these negative interactions through my carelessness, thoughtlessness, and ignorance. That would be comforting, wouldn't it?