My econ professor.

She gave us a computer-based take-home test two weeks ago and told us to use our notes and things for it. She grades it and then takes points off because we plagarized our notes!
I went to discuss my test with her during her office hours one day and you know what she told me? That my writing was too good so it HAD to have been copied/paraphrased. I write for the college newspaper and I had a paper published in a freshman "Best of Writing" book last semester. So uh, YES, I can write well! She wouldn't hear any of it.
So I was and still am pretty mad about it.

I got a 60 on a test that I'm going to have to do a ton of extra work to make up for.