The Land Before Time. *facepalm* Just, The Land Before Time
Okay, I will admit--I loved the first movie as a child. Even now, as an adult nearly 24 years old, I still have fond memories of the movies because I will still watch it with younger children I'm babysitting (on the rare off-chance I'm actually DOING so for my friends or cousins), and the second one wasn't bad. But then things started stagnating after the third one, and by the fourth the whole shebang was just getting old, and I didn't see it.
After a while, though, it was like...every year a new Land Before Time came out, and I recall the commercials and remembering getting ever more incredulous that they kept increasing the sequel numbers....and then, eventually, a TV series of its own, which seems to have finally killed the franchise after an otherwise successful run (with the series having run about...what...50 episodes or something)?
Seriously, though, 13 films in the series AND a TV show? Where does it end?
(Of course, I really shouldn't say anything about this as this same argument could be supplanted to other works with just as many installments in its OWN franchise. Mario, Mega Man, and Pokemon spring to mind right off the top of my head but I'm sure many, many other examples could be named...)