Dallas, determined to top this retarded publicity stunt, years later opened a season by declaring everything that happened in the season before it was a dream.
Why it Works:
Production schedules force most shows off the air for months, up to a year in some cases. The problem has always been that fans can wander off during the down time, so cliffhangers keep people talking through the dry months (in the case of "Who shot J.R.," the next episode got a then-record 83 million people to watch).
And, once the show comes back, who cares that we bailed out of the cliffhanger with an unsatisfying resolution? You should just be glad the show is back at all, you ungrateful fuckers!
Why it Shouldn't:
It's in these cop-outs that a cliffhanger is revealed to be purely a marketing gimmick, having no actual impact on the storyline. These cop-outs let the writers off too easy, since they get to put the character through some kind of life-changing trauma, then just have them get over it (Jack Bauer recovers from his lengthy Chinese imprisonment just a few hours into the new "day.")
Where's the crippling depression that leads to alcoholism, or the post traumatic stress and years of counseling? They turn our surviving heroes into heartless bastards who don't care about anyone or anything for longer than a 2-hour season premiere.