Those sound like things Redd Foxx would have said in real life.
Early episodes of Doctor Who were prone to this. Episodes were recorded as if they were live broadcasts. Only the worst mistakes were given a second take. For minor stuff they would just carry on.
Costner again: In Robin Hood, Prince of Thieves, he ad-libbed the line “Right here?” after being told “Wait here.” You can see it caught the woman he was talking to off guard, but she recovered and they kept it in the film.
I’ve never been a fan of Costner, but it seems he had a habit of ad-libbing. The “butterfly kiss” he had his daughter give him in The Untouchables was not in the script.
In The Godfather, Lenny Montana was supposed to congratulate Don Vito in the wedding scene. The guy looked the part, but he kept flubbing his lines due to nervousness with working with Brando. Coppola kept it in, then shot several scenes of the guy practicing his speech in the mirror and it changed from a flub to a character element.
I don’t know for a fact that this was a blooper, but I’ve always thought it must be.
Take a look at this scene from Abbott and Costello Meet Frankenstein. At about 30 seconds in, Costello points to his right and says “I was reading this sign over here…” Then he sees that the sign is not there, but has fallen to the floor. He kneels down, picks it up, says “This one down here,” and goes on with the scene.
There’s no reason to put a little thing like that into the script. More likely the sign simply fell down, and Costello, being a pro, dealt with it and carried on. A&C came out of vaudeville, and would be used to covering up little flubs like that rather than stopping to do it again.
There was some recent episode of something where someone standing or walking by a wall causes a framed photo to fall off it (which had no reason to be scripted) but I can’t remember what now.
We are currently going thru Mork & Mindy as our old sitcom of the night. With Robin Williams riffing it’s hard to get a clean take.
One thing I’ve noticed is the coats on the coathook on the door of Mindy’s apartment. A coat will fall off it soon after being put up, forcing the actor later to pick it up off the floor when they leave. In one case so far the actor instead of taking their coat took the other person’s coat rather than bend down and pick it up.
Usually such things would be noticed and the bit reshot, but I think just trying to get thru shooting with Williams was trying enough without doing even more retakes.
One really odd “mistake”. In one episode there was a ripple in a rug which people kept tripping over. No one talked about it or anything. I think someone had initially tripped on it and they decided to leave it in and the others went with it.
On a Star Trek Voyager episode I remember someone grasping a handrail on the Bridge as he passed by. The handrail clearly moved a few inches, but the actor just kept on going, and they used the take. Not exactly the rugged construction you’d want on a starship!
In Rumble in the Bronx, Jackie Chan jumps from the dock onto a hoverboat. He landed badly and broke his ankle. He had to wear a cast that was painted like a tennis shoe for the rest of the shoot.
The ankle-breaking scene is in the film. I can see why he wouldn’t want to re-take that one.
Another SNL one, just a couple weeks ago John Mulaney was on playing the proprietor of a bodega whose bow tie goes crooked, then falls off, he picks it back up then stuffs it in his pocket. It’s a very funny skit:
In Boogie Nights, William H. Macy’s character is complaining about his wife having sex with another man out in the driveway surrounded by a watching crowd. He shouts, “My wife is over there with somebody’s ass in her cock!”
It’s just my theory, but I think he flubbed his line and they left it in because it’s the kind of verbal flub a very upset person might make.
Rocky III - Mr. T comes down some stairs before the fight and sees Rocky and clearly says “Stallone! Balboa!”
Tom Cruise broke his ankle in the most recent Mission Impossible movie. They left that in the movie as well.
The “I’m walking here” moment in Midnight Cowboy should also count as a mistake as the car almost hitting him was not planned.
That reminds me of a scene in Collateral where Tom Cruise is chasing the main character, he trips and stumbles over a chair, apparently it was accidental but was left in. It does look too natural to be scripted.
https://www.youtube.com/watch?v=3j01f25dsNI (some violence and poor video quality)
Hands down, my favorite “throw it in” moment is at the end of the Seinfeld episode “The Parking Garage” when the car doesn’t start.
In the MASH episode where Henry is discharged, Abyssinia, Henry, when Radar comes into the operating room to tell the people about the plane crash someone drops a surgical tool on the floor. According to one of the retrospective shows, that was not planned.
In The Dark Knight, when The Joker blows up the hospital, it stops in the middle of the destruction for a few seconds. Heath Ledger pauses curiously, keeps pressing the button, and then the rest of the building blows up spectacularly, and Ledger runs the hell out of there.
ETA: Actually, TV Tropes says it was deliberate!
A “blink and you’ll miss it” moment happened in the first episode of the show Pen Fifteen–a character drops her book bag out of a car and drumsticks go flying out of it. After that moment the scene cuts back to the characters inside the SUV and never shows anyone picking up the drumsticks, so I don’t think it was intentional.