- The series 4 episode "Negative Reaction" Columbo goes to a homeless shelter to look up a drunken witness, except the nun mistakes him for a homeless person while being very sweet and genuine, and tries to find him a nicer coat. When he eventually tells her he's a police officer she presumes he means that he's undercover and that she won't tell anybody. (Either that, or she thinks he's delusional and only believes he's a cop.)
- In that same episode, Columbo pulls up to the scene of a crime, which happens to be a defunct auto shop. The officer on duty initially assumes that Columbo is there to get his car looked at and tells him the place is closed. Columbo identifies himself and the officer tells him where to find the man he's looking for. Columbo attempts to start the car to drive to the designated area, but it stalls out. He says, "I'll leave it here," and then leaves the car, unlocked and with the window rolled down, with the officer, who throws up his hands in exasperation.
- In the episode "Mind Over Mayhem," Columbo is introduced talking to a school official, who informs him that he will have to withdraw his student. It turns out it's an obedience school and they're talking about Dog. Then when Columbo gets called on the case:
Columbo: "Could I just leave him here for a couple hours while I go to work?"Official: "I'm afraid not. He demoralizes the other students."
- In "Undercover," I laughed out loud at the fact that twice, while undercover as "Artie Stokes" and being sent to recover pieces of the puzzle mystery Irving Krutch has placed on him, Columbo approaches both Mo Weinberg and Geraldine Ferguson and both of them are fully convinced he's a cop, even when he says he isn't. The first scene with Geraldine is funnier because she's played by Shera Danese, Peter Falk's wife.
- This becomes even funnier when, after changing back into his usual clothes, he goes to visit the "D. Mc Nally" on the list and is immediately mistaken for a hobo.
- At the end of the episode An Exercise in Fatality, Columbo is rummaging around in his bag for the evidence that will prove the murderer guilty (while the murderer waits, fuming) and pulls out a squashed package:
Columbo: "Oh, that's my lunch; that don't mean nothing..."
- A small bit in The Most Crucial Game: the murderer travels to and from the scene of the crime disguised as an ice cream truck driver. On the way back, he helps himself to a popsicle.
- In The Bye, Bye Sky-High IQ Case, Columbo meets a witness in a restaurant, unconsciously bringing along a donut he picked up along the way. A surly waitress (played by a pre-Halloween Jamie Lee Curtis) tells him that he can only stay if he gets rid of the donut and orders something from the menu instead. Columbo takes the menu, studies it carefully, and orders...a donut.
- The series 5 episode Last Salute to the Commodore features not only a rare whodunit twist on the series instead of the usual howshegonnacatchim, but it also portrays Columbo at his snuggliest, constantly invading Charles' (Robert Vaughn) personal space to the point of repeatedly hugging him or sitting on him. Actor Robert Vaughn can be seen barely keeping a straight face during these scenes.