This might be blasphemy, but I'm interested in the times you find yourself questioning Columbo's logic when working out a case. I have sometimes thought that I could easily end up being a murder suspect given some of the conclusions Columbo makes...for example, often assuming that people are more orderly and predictable than I have ever been.

For example:

In A Friend in Deed, Columbo works out that Janice Caldwell was murdered earlier in the day through the timing of phone calls and whether or not she answered them. Specifically, he assumes that she definitely would have answered a phone call if she were alive and home.

But that wouldn't be the case for me at all. Even before answering machines, I would skip phone calls if I didn't feel like answering them at the moment. I assume that people will call back if it's really important. And that's not even mentioning the fact that Janice might have stepped out to the garage or the yard for a moment or been in the bathroom or been doing something else that prevented her from answering the phone right then.

Another example: In "Forgotten Lady," Columbo finds out how many days Grace Wheeler's husband has owned the book he was reading, and he assumes that there is a turned down page for each night since he bought the book. But what if he skipped reading one night? Or fell asleep while reading? Or just didn't bother to turn it down?

And in "Now You See Him," I have always been unconvinced by Columbo's logic about whether Jesse Jerome opened the door for his murderer. He was unable to think of a way the body would have landed the way it did (shot in the front, falling backward) if the murderer opened the door. But I can think of one. Suppose Jesse Jerome opened the door, and Santini already had the gun pointed at him and told him to put his hands up? Jerome might well have backed away slowly, hoping that the murderer wouldn't shoot him. Santini might have enjoyed watching him back away in terror and let him go eight feet before shooting him. Of course, Columbo was right in this case...but if he wanted to know whether Jesse Jerome or the murderer opened the door, he could have checked the lock for scratches from the outset.

It's been pointed out before, but in Try And Catch Me, Columbo assumes that Edmund and Phyllis had a bad marriage from the lack of photos of her, but of course a grieving husband could get rid of the photos during a dramatic moment (just like an ex-husband, but for other reasons), or at the very least could put them away carefully. It's a missed opportunity for Abigail that she doesn't mention that.
I have to admit, one of the few things that make Edmund look guilty to me is that quick little smirk that he gives at Abigail's photo of Phyllis, but it's not as if Columbo sees that.

I agree. The one I always found easy to explain is in Forgotten Lady and the extra time of the film running. Grace could have gone to the bathroom which would account for the extra time or have dozed off and woke up to the film having broken. She was older and it was late at night, so a jury would easily believe she fell asleep briefly while watching or had taken a bathroom break. Either would easily account for that small amount of extra time.

Going back to Forgotten Lady. Grace could claim she fixed the film immediately but stopped it to use the restroom therefore accounting for the remainder of time And it explains why the film ran longer.

Despite my affection for the episode, I admit that is a problem in that Columbo just assumes that Grace would automatically resume watching after fixing the film. Of course that I think is at heart perhaps the one great flaw of Columbo's methodology in that he so often assumes all people react a certain way and that isn't how it is with all individuals.

The bigger problem with "Forgotten Lady" is why didn't Raymond arrive earlier at the time when he should have assumed the film would be over?

Milo Janus incriminating albi in An Exercise in Fatality has always been a head scratcher for me...

I'm not sure if I'd characterize a lot of this as bad logic. I think it's more his methodology. He often says "gee that's funny", "or things don't add up." Often he's not going after airtight clues with perfect logic. Rather he's stacking up a bunch of clues that when added up point to the suspect. One example is in Death Lends a Hand when he's in the suspect's office and says that the suspect being left handed (he was ambidextrous)is a coincidence since they were just talking about a left handed murderer, and then the punchline, he says this case is just full of coincidences. He already had him pegged anyway as soon as he felt the ring on his left hand with the palm reading ruse. Again that by itself wouldn't prove anything but it leads Columbo in the right direction and to the final setup to trap the murdererer with the final piece of evidence that nails him.

I would also be a prime suspect for Columbo because when I am coming back home I don't yell "honey! I am home!". I am just coming home :)