I had one recently that (when changing / creating the password) would allow you paste into the "new password" field but not the "confirm password" field. Super annoying.
I just opened dev tools, pasted it into the "value" property for the control, and kept on truckin'. Just nuts that had to be done though.
I recently finished my degree, and exam-heavy courses were the bane of my existence. I could sit down with the homework, work out every problem completely with everything documented, and then sit to an exam and suddenly it's "what's a fluid? What's energy? Is this a pencil?"
The worst example was a course with three exams worth 30% of the grade, attendance 5% and homework 5%. I had to take the course twice; 100% on HW each time, but barely scraped by with a 70.4% after exams on the second attempt. Courses like that took years off my life in stress. :(