The woman who accuses Monk of stealing her necklace shouldn't have the necklace inside the asylum in the first place. For both safety and insurance reasons, patients in mental facilities aren't permitted to keep any potentially harmful jewelery, including pins, broaches, earrings, belts, beads and necklaces.

Monk is obsessed with straightening things, particularly pictures on walls. Yet when Sharona brings him a picture of Trudy, it's taped to the wall at an extremely crooked angle, and he doesn't seem to notice.

Mr. Monk and the Billionaire Mugger

It's Spring in San Fransisco in this episode: warm with light rain and people outside in shirtsleeves. That is, until Monk goes to visit Kelly, when it suddenly becomes Winter. Everyone's bundled in heavy coats and it's sleeting. After Monk leaves Kelly's house, it becomes Spring again. This blooper was due to extra footage left over from the pilot, which the producers decided to use as filler in this one.

Mr. Monk Goes Back to School

At the school tower murder scene, Randy's coat is buttoned up over his tie, but changes suddenly when Stottlemeyer says, "OK, bring him up." The coat is immediately unbuttoned and open all the way in the very next shot.

Mr. Monk Goes to Mexico

Dr. Madera hands Monk a coroner's report, and Monk reads aloud from it -- in English. We know Monk doesn't speak or read Spanish (he wouldn't need a phrasebook if he did), so he isn't translating the report. So, why would an autopsy report in Mexico be written up in English???

Trivia: The two Mexican cops Monk is helping in this case are deliberate parodies of Stottlemeyer and Disher, right down to their suits and ties, their attitudes, and the Captain's mustache. Even the Lieutenant's name is a joke on Disher. "Plato" is Spanish for "dish."

Mr. Monk and the T.V. Star

Trivia: Marcy, the obsessed fan of Brad's crime show, complains bitterly about his series changing its theme song. This was written as a little joke on "Monk's" real life fans, many of whom protested the show's 2nd season musical change from Jeff Beal's instrumental to Randy Newman's vocal theme. Newman's vocals opened this episode as usual, but after Marcy repeats her "don't change the theme song" mantra at the end, Beal's theme was brought back to play over the closing credits. It's been used at the end a number of times since.

The blood stains on Brad Terry's sweatshirt change positions after he runs back into the house. A few shots later, they're suddenly so faint they're barely visible at all anymore. Blood stains don't fade, at least not in just a few minutes.

Mr. Monk and the Missing Granny

The SFPD fails twice to trace the kidnapper's call because he isn't on the line long enough. This is an erroneous holdover from *really* old movies and the days before digital & computer technology. Phone calls have been instantaneously traceable since the 1970s.

Mr. Monk Takes Manhattan

When Monk is lost in the street crowd after getting pushed into the subway car, his left shirt collar is sticking up over his coat. It's still up when he puts his hands to his head, but is tucked neatly back in in the next shot, though he still has both hands on his head. A few seconds later, it's the right collar flap that's sticking out instead.

Mr. Monk and the Panic Room

Darwin the chimp pulls a large blue bowl from Monk's kitchen cupboard and throws it on the floor, breaking it. We cut to a close-up of Darwin spinning, then pull back as he starts pulling out glasses - and the blue bowl is back on the shelf, intact. When the angry landlord enters, Darwin pulls the same bowl from a different shelf and throws it again.

All the dishes that are usually neatly arranged in Monk's kitchen cupboards (pots, pans, stacks of plates etc.) have been replaced here by cheap plastic ware, so that Darwin the chimp can pull them all out and throw them. Though we hear shattering-glass sound effects as they supposedly hit the floor, the dishes Darwin bangs together and throws are very obviously plastic.
 
Mr. Monk and Little Monk

In a flashback to 1972, the 5-dollar bill held up by the school principal is an old bill appropriate to the era, at least in the full shot. Unfortunately, in the close-up/insert, it's a new bill, not issued until the 90s, with Lincoln's head much larger on the face. The principal's signature on the bill also moves, from the lower corner on the old bill to the upper corner on the new/wrong one.

The photo of Patty Duke taped inside Little Monk's locker door disappears and reappears twice as the kids are standing in the school corridor. It's also a little odd in this episode that the school kids are talking about watching "The Patty Duke Show" and "The Munsters" in 1972, considering that both shows went off the air several years before that.  Yeah, both went into syndicated reruns almost immediately. It still seems like an anachronism, though, because the kids are discussing the shows as though they are current.

When the kids are standing in front of the lockers, one of them is holding Monk's clarinet. The position of the instrument in his hand keeps changing between shots, from bell-up to bell-down, then bell-up again.

Mr. Monk and the Girl Who Cried Wolf

About midway through, the new nurse is sitting on Monk's kitchen counter eating a sandwich. She puts the sandwich down on a plate as she hops off,  the shot switches to another angle to include Monk as she walks away,  and the sandwich has suddenly jumped off the plate and is now lying on the counter a few feet away. Neither of them had time to pick it up or move it.
 
Mr. Monk Takes His Medicine

The medicated Monk accidentally squirts ketchup on his shirt when he's talking the car salesman's ear off in the diner. A few seconds later, however, his shirt is completely clean again.

In Stottlemeyer's hospital room, a medicated Monk finishes off the leftover pudding from the food tray. Then, while he's talking to them, the pudding smeared on his upper lip disappears and reappears between shots.

Mr. Monk Gets Drunk
 
Monk and Natalie question the landlady, Sylvia, about the missing guest. Every time the camera angle changes, Sylvia's arms change from being crossed in front of her to hanging loosely at her sides.

Mr. Monk and the Game Show

The plot hinges on Monk solving the murder live on the air, so the father-in-law's game show is said to be broadcast "live from Hollywood," even though "Monk's" producers were undoubtedly aware that TV game shows haven't been aired live since the cheating scandals of the 1950s. In fact, they're taped months in advance.

Mr. Monk & the Kid

In the opening sequence, the uniformed cop who finds toddler Tommy holding the severed finger bends down and says, "What've you got there, big guy?" In full shot, the cop is bare-handed. But when we cut to a close-up in the middle of his line, he's suddenly wearing a latex glove.

Mr. Monk Gets Stuck in Traffic

Throughout the highway driving sequence in the beginning, Natalie's rear view mirror disappears and reappears repeatedly.

The VW Beetle that slides out of the dump truck and rolls over is noticeably not the same car the victim was driving earlier. It's a lighter color, and is already badly dented, even before it's wrecked.

Monk inspects the wrecked VW Beetle and notes that "the air conditioning is off." But it's a 1973 VW: they didn't have A/C, and did not have enough voltage to add it.

Mr. Monk and the Red Herring

Monk empties a pocketful of pushpins onto the science teacher's counter top. One rolls to the very edge, separate from the others. A few minutes later, the stray pin is missing. Just before Monk and Natalie leave, however, it reappears on the counter edge.

Mr. Monk Gets Fired

In the opening scene, the orange-and-white scarf that Paul Harley uses to blindfold Lorissa changes positions and color patterns repeatedly between shots as he escorts her from the pool to the garage.

SFPD can't get any evidence from the murder scene because the killer bleached down the garage. But bleach, as Monk learned to his horror in "Mr. Monk Takes a Vacation," does not destroy blood or other bodily fluid stains, even if you can't see them with the naked eye. Luminol and a black light is all they'd have needed to nail this murderer - but then it would have been a much shorter episode.

Mr. Monk and the Other Detective

During Monk's therapy session, Dr. Kruger places his black folder on the arm of his chair. Every time the camera angle changes, the position of his right arm shifts from resting in his lap to lying on top of the folder.