The Finale, especially the second part.
1. "Oh yes I understand now. You are all good guys. I will order the Jem'Hadar to disarm immediately and surrender to be judged for my war crimes."
2. "Dukat, you are a meanie! Stop playing with fire or I'll confiscate the book!" Big fight then "AAAAAAAAAAAAAHHHHHHH!!!"
3. "Kasidy, I have responsibilities in the Wormhole. The Prophets need me. Don't tell the baby in your oven that I'm a deadbeat dad and be nice with Jake. I'll be back one of these days."
4. "Kira, I have responsibilities in the Link. The Founders need me. I know you need me too but frankly, after all those years stuck in that monstrosity of a station, I want to take a long break. Ta ta!"
5. "Well now I know how far those spots go, and I promise not to tell Miles, even if I'm pretty sure Worf told Martok already."
And so many other irritating ways to tell us that DS9 ended once and for all. Thank heaven for fanfic!
While I don't agree that the finale is among the worst of the series, I do have issues with it:
1. Sisko has an epiphany/vision (off screen) telling him that he must go to the fire caves. Next scene, Sisko confronts Dukat in the fire caves. Despite demonstration of immense power, Dukat is defeated by .. being tackled. All in a matter of minutes. It seemed so rushed and shoehorned in. Not to mention anticlimactic after being built up all season.
2. Sisko the prophet visits Kasidy in a vision, but not Jake?
Other than that though, I had no qualms with the finale.