Deliberate mistake: Both in the first scene and last scene of the movie, we see Yolanda and Ringo starting the robbery by jumping from their seat and start threatening the costumers. In the first scene, Yolanda says "And I'll execute every motherfucking last one of you." But in the last scene the line changes to "and I'll execute every one of you motherfuckers". (00:04:40 - 02:18:00)
Suggested correction: Tarantino has explained that this is not an error, rather, he did this on purpose. When we first examine the scene, we are seeing Ringo and Yolanda's conversation from their perspective. Obviously, because this is their conversation, what we hear first is probably what was actually said. However, at the end of the film, what is said is different because we are no longer viewing the situation from Ringo and Yolanda's perspective, but rather everyone else in the diner, most specifically Jules.
Sounds like a typical Tarantino excuse for a stupid blunder.
I believe about 70% of the so-called mistakes called out here are really cinematic techniques to show points of view, highlight significant action, and underscore dramatic moments.
Deliberate mistake: Twice in this film Axel is shot at by multiple gunmen using automatic weapons at close range - and they all miss. In the Earthquake theme ride the bullets ricochet of the rails at Axel's feet. Why are they all aiming low? Why don't they raise their aim? In the park outside he hides behind a perfectly ordinary park bench and the bullets hit the wooden slats. Not one goes through the open spaces between them? I know bad guys can't shoot straight in the movies, but this is ridiculous ...
Deliberate mistake: When the crow drops Shelley's ring into Sarah's hand at the end of the film, the sound of metal upon metal is heard. (01:30:00)
Deliberate mistake: At the end, when the applause sign falls on Rocco's mom, it should stop working. (01:10:35)