I have always maintainted the Paul Galesko ("Negative Reaction") was incredibly stupid parking his Rolls-Royce outside the cheap, seedy motel Alvin Deschler was staying in. I certainly notice unusual, expensive cars and I am no expert so it is likely someone working there would comment on it if they had seen it. Then, of course, there was the big boo-boo of forgetting the little scraps of paper. Another incredibly stupid thing to do was to invite the attractive, provocatively dressed Miss McGrath out to dinner, right in front of Columbo at Frances' funeral! How insensitive can you get, especially considering how well Galesko played the "grief thing" when her body was discovered?

The entire premise of "Dead Weight" is stupid (this is really one of the worst episodes). Didn't Eddie Albert realize that
playing up to witness Suzanne Pleshette would look funny to Columbo, even if he succeeded in convincing her that she didn't really see what she thought she saw.

"Stupid" is strong language. As an alternative, here is my list of questionable things done by the villains aside from committing murder...

Prescription: Murder
Ray Flemming staged that scene with Joan Hudson on the plane so dramatically and loudly, creating more of a chance that one of the witnesses would recognize that his partner was not his wife Carol. The alibi could have been established more subtly, such as Hudson quietly leaving the plane, informing the stewardess, and perhaps one more employee at the airport terminal.

Ransom For a Dead Man
Leslie Williams should not have used the very cash from the false kidnapping to pay Margaret. A promissory note would have seemed more logical.

Murder By the Book
Ken Franklin should not have deposited the $15,000 back into his account so quickly.

Death Lends a Hand
Columbo said it himself: "You never should have let me read your palm."

Dead Weight
Martin Hollister should have dumped the body in an alley and made it look like a mugging rather than disposing of it at sea with his incriminating boat.

Suitable For Framing
When Dale Kingston entered his apartment and observed that Columbo was sleeping, he should have put the paintings safely away before waking him up.

Lady in Waiting
Beth Chadwick should have been more of a sports fan, recognizing that the incriminating newspaper had late scores.

Short Fuse
Roger Stanford should have been more confident in his well-planned scheme to recognize that the gas tank could not have so coincidentally blown up on the very occasion on which he plotted the cigar box to do the same.

Blueprint For Murder
The killer admitted it: "Should have left it where it was."

Etude in Black
Alex Benedict should have typed the "suicide note" after committing the murder, right there in the apartment so he did not have to take the paper out and put it back in again.

The Greenhouse Jungle
Jarvis Goodland should have been satisfied with half of the money, which would have been plenty, especially in 1972.

The Most Crucial Game
Paul Hanlon should have been a hockey general manager. The newly-imposed NHL salary cap would have lessened his headaches.

Dagger of the Mind
They should have disposed of the umbrella in the river.

Requiem For a Falling Star
Nora Chandler should not have talked about the $2 million dollar swindle with Mr. Fallon prior to the case. His admission that they discussed the whole thing beforehand and came to an agreement lessens the shock associated with her supposed confession.

A Stitch in Crime
Barry Mayfield should not have tried to make the murder of Sharon Martin appear to be drug-related. He was one of very few people with access to where the morphine was kept.

The Most Dangerous Match
Emmett Clayton should have packed both toothbrushes, just so there would be no mistake.

Double Shock
There should have been a smarter long-lost triplet.

Lovely But Lethal
Even when pressed, Viveca Scott should not have been so quick to admit that she uses a black eyebrow pencil to do her beauty mark.

Any Old Port in a Storm
Adrienne Carsini should not have been so arrogant in his comlaint about the wine. It resulted in his demise.

Candidate For Crime
Nelson Hayward should not have made that call to the police so soon after 9:20.

Double Exposure
Bart Keppel should have disposed of that converted after that very first night.

Publish or Perish
Riley Green should have had lunch with Ms. McCray before Columbo did.

Mind Over Mayhem
I agree with a previous post that the match should not have been left around, especially by a scientist of such precision.

Swan Song
Tommy Brown should not have thrown the thermos bottle overboard.

A Friend in Deed
Mark Halperin should have authorized a huge raise for Columbo years earlier so he did not have to live in an apartment fit for a struggling burglar like Artie Jessup.

An Exercise in Fatality
Milo Janus should have used a slightly lower-weighted barbell to set up the supposed accident because Gene Stafford had not tried to lift that much weight before.

Negative Reaction
Although we are glad he did, Paul Galesko should not have gone for that camera.

By Dawn's Early Light
Lyle Rumford should not have admitted that he personally saw the cider. A safer story would have been that he received an anonymous tip.

Troubled Waters
Haydn Danzinger pushed his luck too much by planting those gloves.

Playback
Why was it necessary for Harold Van Wyck to take that paper invitation to the art gallery? The main woman in charge there seemed to know him very well, suggesting that his possession of the invitation would not have mattered.

A Deadly State of Mind
Marc Collier should not have made it look like Nadya had killed her husband. The autopsy determined that the force of the blow was too strong to be committed by a woman.

Forgotten Lady
Grace Wheeler should have married Ned Diamond.

A Case of Immunity
The fact that Hassan Sallah was one of few people with access to jam Hakim's rifle was too tell-tale. He should have manufactured a story such as his key to the room being stolen.

Identity Crisis
Nelson Brenner should have listened to classical music on his way to work the morning after the murder.

A Matter of Honor
Luis Montoya should not have told anyone in advance that he intended to drive the hard top car to San Diego. He should have swallowed his pride and driven the car without it being waxed.

Now You See Him
Santini should have looked more closely at that ribbon.

Last Salute to the Commodore
Swanny should have disputed Columbo's claim that he said "Tisn't" by saying that he was simply sneezing and the sound resembled "Tisn't."

Try and Catch Me
Abigail should not have been so quick to admit to Columbo that she had the keys.

Murder Under Glass
As pointed out by Columbo, Paul Gerard should have acted a lot more concerned for his own health upon being informed a man with whom he had just dined was killed by poison.

Make Me a Perfect Murder
Kay Freestone could have gotten rid of those incriminating gloves.

How to Dial a Murder
Considering Eric Mason's expertise, he could have manipulated his dogs in an even more clever manner--such as creating multiple kill commands and raising more of a suggestion that it was a random act of uncontrollable violence.

The Conspirators
I agree that the bottle was too incriminating, and in honor of the occasion: "This far, and no farther."

A Friend in Deed
Mark Halperin should have authorized a huge raise for Columbo years earlier so he did not have to live in an apartment fit for a struggling burglar like Artie Jessup.

Forgotten Lady
Grace Wheeler should have married Ned Diamond.
————————————————————————————
This 2 really make me laugh

And another from Negative Reaction...why did he leave those pictures in the fireplace? Dumb!!

Great post David!

Oh...and by the by....it was my thread so I carefully and methodically chose the word Stupid!!

Yeah, fantastic post David. A lot to take in there...

After that post, it's pretty well covered, but I'll put my two cents in...

The ending of "High Sky IQ" was just so wrong. That was a great murder that was ruined by a short running time and a stupid mistake at the end.

Also, although it's a first rate episode with one of the greatest final clues ever, Oscar Finch in "Agenda for Murder" is supposedly one of the state's greatest criminal attorneys yet he leaves such an obvious clue at the scene of the crime.