Has there been a more hated series finale than that of Seinfeld? Despite being watched by over 76 million people when it aired on May 14, 1998, the general consensus has been that the two-parter appropriately named "The Finale" is “meh” at best. Even The Sopranos' infamous cut to black had about half of that vocal fandom's approval. There have been many zeitgeist-grabbing shows that didn't stick the landing, but Seinfeld particularly fell on its face.
Source:https://www.cbr.com/seinfeld-tv-show-finale-criticism/