I loathed quite a bit of season 4. It was the first season post graduation so it was always going to be tough as all US TV teen shows struggle come graduation. Dawson's Creek (as far as I can remember) tied itself in knots trying to get all of its characters in Boston. Veronica Mars got cancelled after just one season of it. Hell, Glee hasn't even reached the main characters' graduation day and its producers are already having a tough time explaining what will happen to them.
So really, it's no surprise that Buffy wasn't great in its first post high school season. There were some stand out episodes, including the aforementioned "Hush", "Restless" and "New Moon Rising" but there was one aspect of this season I particularly disliked and that was The Initiative.
So, it makes sense to name one of the Initiative heavy episodes as my least favourite episode I guess and I'll go with the aptly named "The Initiative". This is when the existence of the creepy government organisation is first revealed and would cue me falling asleep for half a season if I were ever to have a Buffy marathon. Lord it's dull and that is all I have to say on the matter.