People who act like that are, IMO, among the most annoying in the world. One person at the Student Financial Aid center at my university had this same attitude (albeit, not to the same degree as your ball of sunshine). Seriously, if you hate your job that much, then quit. If you want to be all-around pissy and miserable, then do it on your own time.
On a side note:
That is the best opening line I’ve seen in a while. 
Thank you very much for making me feel better about my crappy-ass community college. It might not be the most glamorous school to go to, but every single person there so far has been polite and even sweet while I’ve asked my bewildered old-person-going-back-to-school nonsensical questions and rushed around to get things done at the last minute.
But, you see, you have arrived at the very heart of her problem. As ThirdCultureKid so eloquently described in the OP, she was bending every effort to attempting to achieve a “non-friendly tone of voice.” That she failed despite her best efforts would be enough to piss anyone off!
In practice, this would strip the flesh from your body one layer of cells at a time, quickly resulting in agonizing pain, and rapidly, death from blood loss.
I think the question is, can a woman even *be *fellated? (Joanie Laurer notwithstanding.)
Her attitude sucks, but putting up with this attitude from students all day might not be putting her in a sparkling mood. It reminds me of a lot of the student drinkers in the pub I worked in while studying for my doctorate. They all knew for a fact how much smarter they were than me, the lowly bartender.
Tell her you would like fries with that class.
And how do you fellate with shark skin? Put it in your mouth?
Yes, but a female can’t fellate themselves. Masturbate, yeah. 
I’m sorry, ThirdCultureKid. I work at a college, and, yes, I do deal with some students who are entitled dickweeds, but most of our students are very pleasant folks. I stay at this job because I like working with students. It’s a shame that some of my co-workers don’t feel the same. (Financial aid office, I’m looking at you. Quit being jerks to my students!)