Toy Story 2 Movie MistakeLet's be honest, sequels rarely live up to their popular predecessors.

With a boatload of cash on the line, who can blame classics such as "Home Alone" and "Superman" for spawning perfunctory follow-ups? Still, that's no excuse for some obvious mistakes. While not every gaffe is cringe-worthy, the "High School Musical 2" goof is especially painful and really makes you wonder who wasn't paying attention.

Here are 15 "oops" moments from blockbuster sequels. As usual, all photos are courtesy of MovieMistakes.