8. American Graffiti
The Ending: After a fascinating, nostalgic passage through the 1960s, a title card before the end credits that of the four main characters, one is killed by a drunk driver in December 1964, and another is reported missing in action in December 1965.
Why It's Infuriating: It's needlessly bleak and thrown in there for no reason. Whereas, say, Stand By Me used the death of a central character as a framing device, here it just doesn't serve much of a purpose beyond saying "life is short". Sure, we were left wanting to know more about what happened to these four guys, but to make it so needlessly bleak smacks of a filming aiming to be "realistic" but overshooting. A sequel, More American Graffiti, explored the deaths of these two characters in more detail, and unsurprisingly, was a critical flop and nowhere near as financially successful as the original.