Revealing mistake: In the early part of the chase scene, when the person hanging the banner swings into the pane of glass, you can actually see it start to shatter before he touches it.
What's Up, Doc? (1972)
Plot summary
Directed by: Peter Bogdanovich
Starring: Barbra Streisand, Ryan O'Neal, Madeline Kahn, Kenneth Mars
When absent-minded Musicologist Professor Howard Bannister (Ryan O'Neal) arrives in San Francisco to try and win a research grant, the last thing he expects is to have his world turned upside down by Miss Judy Maxwell (Barbra Streisand), a girl who causes chaos wherever she goes. In the space of two days he gets mixed up with a millionnaire, jewel thieves, kidnappers, a spy and a government agent; accidentally sets his hotel room on fire, finds himself sitting on a grocery deliverer's bicycle inside a Chinese Dragon and ends up dressed as a Cantonese Mandarin in a car chase through the city in a stolen VW Beetle.
Lindsey
More mistakes in What's Up, Doc?
Hugh: I find that as difficult to swallow as this potage au gelee.
Judy: How would you like to swallow one sandwich d'knuckles?
Trivia: In addition to Ryan O'Neal appearing in this film we also see his brother Kevin O'Neal (delivery boy), and his mother Patricia O'Neal (woman on plane).