I'm interested in hearing what you think was the saddest television episode you have ever seen. I'd prefer if you stuck with the plot instead of dwelling on the thought that, in the case of a series finale, your favourite show was now gone forever.
Personally, I feel "Jurassic Bark" an episode of Futurama is the saddest episode I have ever seen of any show. **Spoiler** Basically, Fry finds his mummified dog in a museum and tries to acquire its remains from the museum. Eventually he does and plans on having it cloned, including its memories. We see flashbacks to the 20th century where Fry finds the dog in an alley and shares his pizza with it. The dog was loyal, following him to deliveries and waiting for him at the pizzeria he delivered for. In the end, Fry finds out that the dog lived for 13 more years after Fry got cryogenically frozen and he thinks that the dog probably forgot all about him so he decides he'd rather not clone the dog after all. As the episode ends, we see another flashback of the dog waiting for Fry the day after he got accidentally frozen and the dog just waits for him outside of the pizzeria for years and years, all this to the tune of "I Will Wait For You".
I actually cried at the end of this episode and I don't remember the last time I cried (if I've ever cried) from a television show.