2. Dallas
Episode: "Return to Camelot" And All Of The 10th Season The Reset Button is a cheap trick employed by writers who have painted themselves into a corner and can't continue without wiping the slate clean. Pretty much all series have done it at some point (think of the final episode of Lost which literally features a hard reset, or "The Big Bang" in Doctor Who wherein the entire Universe is rebooted) but few so sloppily and egregiously as the cliffhanger to end the 9th season of Dallas where Pam is more than a little surprised to see the dead Bobby Ewing lathering up in her shower. As the following season made clear, the entire year had been little more than Pam's dream, which meant Bobby was no longer dead, and all the events and story development of the past season were reset. Fans were more than irate, having spent a year watching a series that meant absolutely nothing.