Anyway, the first 12 issues set all this up and then the last issue tears everything down when the Hulk's ship spontaneously explodes and destroys the whole planet to set up the "World War Hulk" storyline where he returns to Earth to kick everyone's asses.
This is something that annoys me and that usually happens in series because you have to prolong the series so you ruin an otherwise perfect happy ending with a lame plot twist. I mean the Hulk had united all these different tribes and become the king and married a chick and knocked her up and then 20 pages later we have to torch all that.
The next morning I watched "Star Trek: Generations" which is kind of the same thing. In "Star Trek VI" Kirk and crew almost literally rode off into the sunset, but then we had to bring Kirk back and contrive a scenario where he could pass the torch to Picard and then dies. It was definitely the weakest entry of the Next Generation movies and really unnecessary.
Another example that comes to mind is "Men in Black II" where we had to throw away the happy ending for Tommy Lee Jones just so that we could make a couple of crappy sequels to make more money. That's the thing, in all these cases I don't think there was much artistic value to these moves. It was just about extending the series to make $$$$$.
Sometimes this happens on a smaller scale to create drama. I remember episodes of "Family Guy" and "Reaper" for instance where a main character gets into a relationship with a girl and once things get serious BOOM! that girl instantly does a 180 to become obsessive and clingy so he has to dump her. The idea is we don't want him to actually end up with the girl because then we'd have to keep her around and that would mess things up, but really I can't help feeling how contrived it is.
I think in part that's why I haven't felt any need to continue the Scarlet Knight series past book 8 or the Chances Are series past Book 3 because both end up with relatively happy endings. If I did a sequel to either I'd have to start tearing that down and really I haven't seen any great impetus to do so. In lieu of money there'd have to be some story I thought really needed told to sacrifice the happy ending I came up with. Or if there's money involved of course...
Are there any happy endings you wish hadn't been wiped away?