21. May (2002)
Although not overtly "scary" in a traditional sense, Lucky McKee's bittersweet masterpiece earns a lot of points for sincerity, compassion, and off-kilter humor. This underappreciated yet undeniably effective horror film works on a variety of levels (hell, even the late, great Roger Ebert gave the film four stars!) but it's at its best when it's focused on the gradual descent of poor May Canady (Angela Bettis), a strange young woman who alienates most of her acquaintances before deciding to build herself a perfect friend. Yes, that's "build" in the Frankenstein sense. May is gory, funny, and haunting. Because, let's face it, we've all felt like lonely May from time to time.