In the scene where Benjamin Danz played by Adam Brody is tied up in the chair caught by Mr. & Mrs. Smith, Mr. Smith says "Why do both our bosses want you dead?...." and then he says, "You on this?" and right at that moment above his head (upper right corner) a little boom mic appears and disappears.
When John and Jane have dinner at home, Jane serves a roast that John describes as "pot roast, my favorite." However, the slice of beef that ends up on his plate is medium rare. Pot roast is always thoroughly cooked and is therefore always served well-done.
Before Jane kills her first mark, she snaps the wrist cover band over her finger on each arm/hand. When she makes it out and onto the street they are no longer attached at the hand as she gets the taxi. When she gets back home, however, she takes them off of her fingers again.
Mr. Smith throws his suit coat into a mailbox when he realizes Mrs. Smith has placed a small bomb in it. Then the Smiths separately race back home. As they approach the house, in one shot, Mr. Smith is wearing his suit coat.
During the chase scene where Mr. and Mrs. Smith are driving a silver Dodge Caravan, he switches with a silver Town & Country several times throughout the scene. The Chrysler logo can be seen on the headrest as this happens. Also, the Town & Country has suede and leather seats, while the Caravan has cloth.
John has a set of cuts on his face that cross each other after he and his wife fight in the house. Over the next few scenes the cuts continually change. The final pattern of the cuts is very different from the way they started.
When Jane and John are in the shed during the final shootout, you can see him putting the bandage on his arm in the background as she looks out the hole in the wall. Then he is rummaging around for something with no bandage on. Then when Jane turns around, he is tying the bandage again.
In the scene when John comes back home after finding out Jane's real identity and John is about to drop the wine bottle at the dinner table, you can see Jane and John holding wine bottles. And when he drops it, Jane moves her bottle out while John's bottle vanishes.
When John is in the elevator 70 floors up (supposedly at her new office) talking to Jane he is shown on camera without sunglasses then in the next shot where they show him on camera he has on sunglasses which he takes off and puts in his pocket.
When Pitt and Jolie are in the sewer hiding from the black SUVs and helicopter before the big shootout, they have nothing on them. When the scene cuts to them running toward the "Home Made" they still are carrying nothing. However, when they get into the store, they are carrying bags full of guns with them.
When the Smiths receive their instructions on where to find "TANK", to take him out, John is told that he will be 10 miles North of the border, and Jane is told that "TANK" will be 10 miles South of the border.
After their house blows up and they are stealing their neighbor's car, you can hear sirens in the background as John backs the car out of the driveway. When a shooter tries to stop them, John backs into him and jumps out to steal the shooters gun and you no longer hear the sirens. Then when John gets back into the car and resumes backing out of the driveway, you can hear the sirens again.
In the shootout in the department store, the second time they go into the elevator (when Jane tries to apologize for the knife), Jane is standing on the left holding an H&K MP5, and John is on the right, when they exit the elevator, Jane is on the right and is holding a handgun.
After John figures out that it was Jane at the hit in the desert, there is a scene where he is speeding down their street, but he is not driving his black Cadillac, instead he is driving the Lincoln Towncar featured later on in the film as the "limo" he steals. In fact, the shot is almost identical to the one later on when he is racing Jane back to the house after the restaurant, right before she rams him. Also, in the same scene, when the car is coming towards the camera, the headlights are on, but once he turns into the driveway, the headlights are suddenly off.
John knocks the jar over with his elbow and manages to catch it, he runs away after the lid shatters. You can clearly see John is holding the jar when he turns, but when the camera changes to in front of John he is NOT holding it.
When John and Jane leave their house prior to it being blown up, they have two guns - a HK USP Elite and a Smith & Wesson Centennial. When Jane destroys the two remaining cars in the highway chase, she does so with a Glock, a gun that they did not have with them previously.
In the chase scene with the three BMWs, there is a wooden cross hanging from the mirror of the Smith's car in all the shots through the windscreen. In the close-up shots of the mirror showing the rear view, there is no cross.
The car from Jane (the Mercedes) is clearly damaged when she escapes the car while John is still in it, as it drives through some bushes. Most likely she lost the car. However, when Jane drives back from the restaurant to her house, she is back in her old car.
When John and Jane finally get off the elevator at home made Jane has a bullet hole on the right side of her shirt, then as she is lying on top of the roof preparing to shoot, there's no longer a bullet hole on her shirt.
When Benjamin is being interrogated by the Smiths the scene cuts to Jane, drumming her fingers on the bedside table. Beside her is a brown phone. When she gets up and grabs the phone a few seconds later, the phone is black.
After the Bogota flashback, John is seen picking up a newspaper thrown on the ground by the delivery boy. The ground and the whole pathway leading to the house is wet since it rained. John shakes the paper to dry it. However, when his neighbor is shown picking up his own paper, the ground appears to be dry and unaffected by the rain.
At the beginning of the chase between the SUV and the three BMW's, John shoots at them. When that proves ineffective both he and Jane say the cars are bulletproof. Then at the end of the chase they are suddenly no longer bulletproof as Jane shoots both of the remaining cars, causing them to crash.
When John and Jane are first having dinner, John picks up his wine glass in his left hand while asking Jane to pass the salt. After Jane says that the salt is between them on the table, the scene cuts back to John suddenly holding the wine glass in his right hand.
When Jane is having champagne after the elevator crash scene, John comes up and places the white napkin over his left arm and picks up the bottle of champagne from the ice bucket. When he is pouring the champagne, the white napkin is wrapped around the neck of the bottle and no longer over his left arm.
When John uses a pipe wrench in a fight, he grabs one pipe wrench and swings it like a bat (using both hands) and moments later he is seen waving a pipe wrench in each hand, flailing them around like nunchucks. How he got the other pipe wrench was not shown.
Towards the end of the movie, Mr. and Mrs. Smith are chased around at high speeds along highways in the greater New York City area. As they zip along one freeway, however, a sign appears on the side of the road. It reads: "Los Angeles City Limits".
When John Smith is firing the Widowmaker missile at Jane, the targeting screen shows latitude and longitude coordinates that place him somewhere in Alaska. When John is trying to break into the prison to retrieve "The Tank," his shown coordinates place him 350 miles off the coast of Spain. Also, if you time John Smith's movement in the pipe, and compare it to the updated coordinates, he moves over 900 feet in 11 seconds, about 55 miles per hour. And when he is climbing the vertical pipe, his coordinates should remain steady. Also, the likelihood of receiving a GPS signal underground in a pipe is slim to none.
When John and Jane are in the elevator in the shoot-out in the "Home made" mall, they each carry a HK MP5, and the cocking handles on both are clearly in the retracted 'up' position, as they are when being reloaded. In this position it is not possible to fire the weapon, which they both clearly do the very next second. If they *were* reloading, they clearly would not just stand waiting with the weapons as they do.
Towards the end of the film, the Smiths take "the Tank" to a motel to interrogate him. When the fleet of spies arrives, they bust down the motel room door, which has the number "49" visible on it. A few seconds later, though, the camera shows a row of doors that the Smiths have broken through to escape, and the number on the door adjacent to their room is "112".
In the scene where Vince Vaughn doesn't "get out of bed for less than half a million dollars", when the reward information and physical description of Jane comes up, her eye color is incorrectly listed as Brown.
After the restaurant scene when John and Jane are driving their respective vehicles back to the house, John calls Jane and she reaches down to activate the hands-free system in her car, at which point the console is revealed, and while there is a beep, the screen is not on and there are no other lights on anywhere in the car, where there should definitely be some, hence indicating that the car is in fact not running. This is shown in multiple shots in which the console is clearly visible and clearly dark.
During the chase on the bridge, with Jane driving the mini-van, she presses the automatic hatch button causing it to open. However, for a vehicle to be able to use this capability, the van must be in park. Of course, since it opened during the chase and as they are spies, it is easy to believe that they made the doors/hatch operate even while driving.
Jane is reading a newspaper named "Prensa Colombiana", a weekly publication issued in Los Angeles by members of the Colombian community, but pretty much impossible to find anywhere in Colombia. These scenes are supposed to take place in Bogota, where a large variety of full sized daily newspapers are published by several editorial houses.
When John Smith shoots the guy Lucky, in the first scene we actually see him with a target, he push's his chair all the way back to shut the door with him still in it and shoots the men. When we get a frontal view of John Smith after he has shot the men, he's getting up out of the chair with it being all the way back up to the table. When did he get up and move the chair back up?
John and Jane appear to break into the Kost Mart. Following this we see a wide shot showing the black SUVs approaching the Kost Mart, and across a parking lot driveway we see the Home Made building to the left. All the SUVs and assassins go to the right, towards the Kost Mart, and we see them searching that building. The team then finds the unlocked Kost Mart door and storms inside. During the shootout, based on the interior signage, all of a sudden everyone is inside the Home Made building.
During the highway chase scene when they run one of the cars off the road into the water barrels, the flash of a detonation charge that bursts the barrels can be seen a split second before they hit them.
When John races home the first time (in the wrong car mentioned in another goof), he slows as he turn into his driveway and the camera angle shows the car's instrument cluster. Not only is it the wrong cluster for the Lincoln Town Car he was just shown in; not only is it dark, indicating the headlights aren't on even though they were just shown to be on; but the only things visible in the cluster are the engine, brake and SRS lights, indicating that the engine is OFF.