[Updated April 30, 2013]
Regardless of the success or not of the seasonal arc, S4 contains two of the most innovative episodes of any TV series ever. Hush is the first of these. It’s a very popular episode, regularly appearing on Top 10 lists and often cited by fans as their favorite episode. There are so many great little details and great scenes that I can’t even try to describe them all.
Worse yet, from my perspective, there’s been so much discussion about Hush that it’s hard to come up with anything new to say. Note, though, that it fits right in with the theme of identity I’ve been discussing, particularly when it comes to Buffy and Riley, but also for Willow as I’ll explain later in order to avoid spoilers now.