It's pretty hard to make me mad. But if you really want to piss me off, then be a teacher who trashes your student with a phrase like "you're hopeless", "anything would be better than that", or "I'm beginning to think that this [...] really sucks."
<rant>
That just happened to two people I know, in different cities. That is not teaching. If you do that, you can't possibly be a teacher, because when you agree to be a teacher you agree to respect the enormous privilege that being a teacher entails. Yes, it's a privilege for a student to learn from a great teacher, but it's just as much of a privilege to witness the personal improvement of a student who works hard, and it's a huge responsibility to take charge of a student's education in any area.
There are some "teachers" who think that telling a student with "no talent" the honest truth is a good thing, because it will save the student the heartache of pursuing something that they're no good at. That is gatekeeping, not teaching. A real teacher knows that any student will be able to achieve a high level of proficiency, given a certain amount of time. The trick is figuring out how to help that student improve most quickly. This is what I think about at night--did I give the right lesson? Am I doing things in the right sequence for this student? How can I describe a technique to this student in a way that will make sense to him? How can I do right by this student?
So when I hear a teacher say "you're hopeless" to a student, I hear it as a total cop-out. A teacher takes what a student is already good at and figures out how to use that ability to improve some other area, which means that a teacher always has to be looking for the good in a student as well as for the things that need improvement. What a huge challenge! Every student has a different background and is good at different things. Harsh words from a teacher mean that the teacher wasn't looking for the good, and that means that no matter how much knowledge that teacher has, the student won't improve as quickly as she could.
In the case of both of my friends, I know the words they received were not just unnecessarily harsh, but also untrue. No teacher, no matter how great a musician/composer/dancer/thinker, should be allowed to take an open, eager mind and squash it with one sentence. That person should not be allowed to teach.
</rant>
Oooooh, I am still so mad that I can't even form coherent sentences. Feh.