There hasn't been a season of Buffy that I have disliked in its entirety. Even though I am a mad, obsessed fan there have been things over the seven years that I havnt liked. Im a good enough fan to admit that Buffy isnt always perfect lol.
Im not the biggest Buffy/Angel fan so season 1-3 being quite Bangel arent going to be my favourites. I liked the freshness and new beginnings of season 4. I would have to say that seasons 4-7 are more enjoyable to me than 1-3.
My overall favourite season is 5. First and foremost because of the characters. Anya being a regular, Giles importance in training terms, more Tara including the Tara centric episode Family. And I guess that I liked the inclusion of Dawn!
Obviously episodes like The Body, The Gift, Family, Forever stick out but I just love the season as a whole.