15 Most Important Buffy The Vampire Slayer Episodes
8. This Year's Girl/Who Are You? (Season 4, Episode 15/16)
It took a while, but Faith finally wakes up half-way through season four, angrier and more vengeful than ever. Using a strange device to switch bodies with Buffy, the rogue Slayer attempts to integrate herself in Buffy's life, giving herself a new look and allowing Sarah Michelle Gellar to pull off a dark and hilarious performance.
Faith's arc from the season three finale until the show's end is brilliant, and it's during Who Are You? in particular that her bad girl act begins to crack, showing a woman who is not nearly as strong or evil as she likes to think she is.
Both episodes also allow more time for Tara Maclay to become a more substantial part of the group, and throws the first of many spanners into the works of Buffy and Riley Finn's relationship. It's a striking story, allowing Buffy and Faith to see each other's lives from a new perspective and letting Faith begin to question her actions.