Bye bye "E.R."

The long-running hospital drama bids adieu tonight with a big lovefest involving all of the old castmembers.

Could be good, could be bad. Probably the latter.

PHOTOS: The 10 worst season finales of all time.

Sometimes, a series manages to wrap up in a satisfying, sensible manner, providing a sense of elegant closure to a well-told tale.

"MASH" did it by ending the Korean war and saying good-bye to each cast member individually.

"Cheers" did it by bringing Diane back for the last few episodes so she and Sam could find some closure to their relationship.

And then, there are finales like these ten, which did everything wrong.