In film, a movie cliché is a line of dialogue, an event, a stereotypical character, or a plot twist that has been seen over and over in films. Critic Roger Ebert began making note of clichés in his columns. Some, such as the spit take, are unique to comedy, and can be appreciated for both their familiarity and surprise.
To its credit, the Back to the Future trilogy has remarkably few clichés in a widely-praised, tightly-written and edited story in which each line of dialogue added to the plot. Examples of clichés that were written into the first film were the interrupted kiss (Marty's attempts to kiss Jennifer are interrupted by Doc, by Mr. Parker, and by the annoying Clock Tower Lady); the villain who allows the hero time to avoid injury (as with Biff and Marty); and the "spit take", as when Marty spits out his drink when he's watched his future mother defy one expectation after another.
The clichés are inverted in other installments of the trilogy, with Marty interrupting Doc Brown's romance with Clara, or Griff not being taken in by Marty's "What's that?" trick that worked with Biff 60 years earlier.