It is night when Ben drives Mrs. Robinson home, yet when they walk through the house to the greenhouse area, it is clearly bright and sunny outside, and the light filtering into the room is obviously natural light from outside, not from electric lights.
When Mrs. Robinson gets Benjamin to come inside her home, she turns on the stereo after making a drink for Benjamin. They go upstairs then, and when Benjamin hears Mr. Robinson pulling up to the house and rushes downstairs, the music is no longer playing.
When Ben and Elaine are at the drive-in on their first date, they are talking and there is a foot just behind Ben resting on what seems to be the edge of the car. The foot seems to belong to someone in the next car. The camera angle changes and the foot is gone.
At the backyard birthday party for Benjamin, his father keeps whispering to him at the kitchen door and Ben replies, hidden just a few inches away. Yet, in the next moment, when Mr. Braddock opens the door for him, he is 20 feet away, fully encased in a scuba mask and cowl, with the regulator in his mouth, and all sound cut off from the outside world.
When Ben is in the hotel bar waiting for Mrs. Robinson, he takes a sip of his drink and the glass has ice in it. When he sets the glass down and there is a reflection of Mrs. Robinson on the glass table, there is no ice in the glass.
The University of California at Berkeley has no electric bells announcing the beginning or end of classes.
When Mr. Braddock introduces Ben and his new 21st birthday present, he walks Benjamin out to the pool steadily maintaining a constant steam of narration. The POV shot of Mr. and Mrs. Braddock show them without Ben hearing their voices as if the frogman suit is blocking all the sound. There is no reason Ben wouldn't be able to hear them clearly while wearing his underwater gear.
When Ben is sitting in bed smoking a cigarette, he reaches up to the shades and when his hand shows up again in the scene, the cigarette is no longer there. In fact he simply switches it from his right to his left hand out of shot before he reaches for the blinds and you can still see the smoke coming up.
At the end, when Ben is trying to get Elaine's attention at her wedding, Carl is seen kissing her. That means the wedding is over (you may now kiss the bride). When she runs off with Ben, she is already married.
The whole point of the scene is that Ben is too late and Elaine is already married, yet she chooses to follow her heart and run away with him anyway, leaving them to ponder to themselves "What next?" as their elation dies down in the final shot of the film.
The whole point of the scene is that Ben is too late and Elaine is already married, yet she chooses to follow her heart and run away with him anyway, leaving them to ponder to themselves "What next?" as their elation dies down in the final shot of the film.
When Benjamin and Mrs. Robinson meet at the hotel bar, Benjamin unsuccessfully attempts to draw the attention of a passing waiter. In the glass wall behind them, the waiter can be seen to stop as he leaves the frame and wait for his cue to re-enter.
When Benjamin and Elaine are in his Berkeley room, at one point his face is full of shaving cream and he starts to shave. When he suddenly decides to stop shaving and wipes all of the shaving cream off with a towel, he has no stubble or growth on his face. He did not need to shave to begin with.
The Robinsons are always able to draw fresh ice from the ice bucket on their bar, even after they have been away at a party, presumably for several hours.
As Benjamin and Mrs. Robinson drive and run through the "rain" near the Robinson house, the lawns and shrubbery in the background are lit by bright sunshine.
At the birthday party for Ben after he has jumped into the pool, as the camera pulls backwards once he is underwater, it is clear that it is not the Braddock's pool. It is far too deep and wide to be the same backyard pool.
When Mr. Robinson sits with Benjamin at his sun-porch bar, he lights a large cigar during their conversation. After its initial puff, the cigar goes out, but Mr. Robinson continues to handle and draw on it as if it were fully lit.
In several scenes when the Alfa Romeo Spider is being driven aggressively, the engine note is a dubbed on American V-8 rather than the burbling four cylinder that it should be.
When Ben is seen crossing the Oakland Bay Bridge on his way to Berkeley, he is driving on the upper of the two decks of the bridge which only carries traffic westbound from Oakland to San Francisco and thus would be taking him away from Berkeley. The only way to get to Berkeley by way of the Bay Bridge is to drive eastbound, and all such traffic is carried only on the lower deck of the bridge.
On Benjamin's driving trips from Berkeley to Los Angeles, he goes through a tunnel. This tunnel, north of Santa Barbara, is actually a northbound tunnel. There is no southbound tunnel.