I'll add to system32's hate on bad finale episodes with Star Trek: Enterprise's "These Are The Voyages". Enterprise was abruptly cancelled in the middle of its best season and got a very ill-conceived finale that focused on characters from a different show remembering completely uninteresting events from a year after the previous episode of Enterprise. What's worse than it being rushed is that it not only wanted to be the finale to Enterprise, but the finale to an entire era of Star Trek, because for the first time since 1987 there wasn't a new show in production, and they absolutely did not have time to meet that expectation. Plus it was unnecessary; if it had never been made, then Enterprise would have still had a decent finale in "Terra Prime". Star Trek: Discovery also had a rushed finale due to an abrupt cancellation, but thankfully didn't feel nearly as rushed in the end.

The Girls und Panzer final episode, the Doraemon final episode, actually, the final episode of a lot of anime I like or have liked at some point.

EDIT: Also, Windows Vista and the first version of XP. 7 is what Vista could've been if done right. XP got really good after a couple service packs.

(ME wasn't rushed, it was straight up shit. "Millenium Edition" more like "MISTAKE Edition")