4. Alf, March 24, 1990
You usually expect a sitcom, especially one that is aimed to a younger audience, to end on a happy note. That was not the case for Alf. Our favorite alien was about to head home to Melmac, but instead was captured by the U.S. Military. This finale was intended to be a cliff-hanger, but NBC never did produce the following episode so viewers could find out about poor Alf’s fate. Hopefully, he made it out alive.