End of term exams that usually last 1-2 weeks. The worst part of existence for a high school or college student.
Finals are an attempt by teachers to prove that you haven't been bullshitting the entire class, which of course you have. Thus, finals week consists of subsisting on copious amounts of caffeine, limited amounts of sleep, and study sheets downloaded from the internet. Also characterized by large amounts of panic and procrastination posts on Facebook and Twitter.
They account for huge fucking amount of your grade, and it is scientifically proven that you never get the grade on your final that you want to.
Bob: I just want finals to be over. This is the worst week of my life.