Symptoms of hellishness: Clearly favoring Slytherin students, constantly berating Harry, sneering.
Student response: Lighting Snape's cape on fire, misplaced suspicion and distrust.
Why you gotta watch it: While Chris Columbus' take on Harry Potter isn't quite as delicious as Alfonso Cuarn's, this introduction to J.K. Rowling's world of muggles and wizards is still pretty magical. Rickman absolutely nails Snape's confounding blend of malice and secret compassion.
Obi-Wan Kenobi is ranked second for almost killing Anakin and then letting him live, causing a ridiculous amount of murders over the next few decades, and economics teacher Ben Stein from Ferris Bueller's Day Off ("Bueller? Bueller? Bueller?") is #1. Umbridge isn't on the list, but that's only because the film adaptation of Order of the Phoenix hasn't yet been released. Once it's out, we figure she just might knock Mr. Stein off the top spot.