DVD Caps Who Are You? 
Break Down
This episode is obviously pivotal in the 'Faith Stakes'. It's brilliant but also annoying. No surprise to learn that Buffy gains absolutely NO insight into Faith what-so-ever. She's treated like trash. In this season (4th) it REALLY is the 'me me me' season. Buffy 1st-3rd season--The 'moralistic' Buffy we actually like, would not condone how Faith was treated. Indeed...how SHE'S treated. But more worried about herself, she doesn't even ponder 'I wonder if Faith was treated this way her whole life'? To Buffy, it's all about escaping and getting her body back. And that truly makes my blood boil.
Faith, on the other hand, literally turns her life around! It basically screams...that if you give Faith a chance, she'll come through. Sadly, we learn that Faith completely loathes herself. She goes from being herself in Buffy's body...to realizing that she can make a difference in peoples lives. From the gratitude of the girl she saves...she remembers what it was like to be a Slayer...rather than a wild child who was right hand to evil. For the very first time in her entire life...she has a glimpse of love with Riley, and is completely thrown by it. For once, not used and abused...but cared for. It frightens her...but also makes her realize that she wasn't living the 'fun' life and that sex isn't all sick games.
It would've been so easy for Faith to board the plane and live life out as someone else. But her realization of what she used to be (like it or not...Faith pre-Mayor DID care about her duty as a Slayer) caused her to go to the church. True, she thought Buffy would be in England...but it still would've been easier for her to flee rather than save the people she did. Again...as I've always said. When 'crunch' time comes...you can rely on Faith.
No coincidence that the 'big switch' take place in a church. That Faith's realization that she loathes herself is 'finding' her TRUE inner self. It's the first step of her ultimate redemption. A realization that (in her eyes) she's lost her humanity. The body that her soul's in, is nothing but a revulsion to her.
Of course, all this sets up the next two episodes...specifically Five by Five. By the time Faith arrives in Los Angeles, she loathes herself 100%. She doesn't care who she hurts or how she acts due to her self perception. She is, whether she knows it or not, suicidal. But I'll get to that in Five by Five.
It's interesting to note at least 2 'Graduation Day pt.1' references. (Although I suppose it's no surprise considering JW wrote it) A recurring theme in this episode is Faith's 'aim for the stomach' approach. She visualizes knifing Willow where Buffy knifed her. Also, when she's dispatching the vampires...her first punch/kick is the same place. Clearly...she feels if she was vulnerable there...then others will be also. I also LOVE the reference to 'Poetic Justice'. It's great! Obviously, Faith remembers Buffy saying :"There's a cure". Faith: Damn. What is it? Buffy: Your blood. As justice goes, it's not un-poetic, don't you think? re: needing Faith's blood to cure Angel in Grad Day 1. Faith thinks Buffy being arrested is 'poetic justice'.
Faith: "On her way to the big house. Cops took her off my hands about an hour ago. Poetic justice." Anya: "How's that?" Faith:"Well . . . she did all those crimes and now she's being arrested. (frowns) I guess that's just regular justice..."
I just LOVE that. It affirms that Faith files things away for future refrence, despite being unsure of the exact usage.