Show: Smallville (The CW)
If you weren't a die hard Smallville fan, you might be surprised to hear that the show lasted ten seasons. You might even be more surprised to learn that Clark Kent (Tom Welling) didn't get that giant "S" on his chest until the very last episode. The circumstances of a show that is meant to end when the main character becomes a superhero creates a strange atmosphere with regard to spoilers. Many fans were careful to dance around the reveal of the suit and Kent's first time flying, but if you were watching the show by this point, you had to know that these events would be the show's grace note. Anyone viewing by that point would only be there to see how the reveal happened. If the reveal of the suit and Kent's flight is a spoiler, then so are the names of the characters and the title of the show.
Whereas many finales trade on building up to a surprising conclusion, this finale built itself up as delivering exactly what you'd been waiting for.