Angel season 4. The whole thing with Connor and Cordelia was just ... so bad that words fail me.

Buffy season 4. Not horribly bad, but horribly boring, and for me it became the point where I started losing interest in the show.

DS9 season 7. New Dax, everything connected to Gul Dukat and his little cult, and overall disappointing series finale.

Roseanne last season. It was all a dream. Yeah, I wish.

Supernatural season 4. Season 6 was far worse, but 4 was the season where the plot took a turn to a direction I didn't like.

Gargoyles: Goliath chronicles. It doesn't exist and nothing can convince me otherwise.

Lovejoy series 5. The beginning of the end. Lady Jane leaves and the whole series loses steam.