This well-known phrase, attributed to various people, basically means that sometimes we hang onto something in the a purely because we like the sound of it. It may be irrelevant, it may be long winded or unbalancing, it may disrupt flow and pace, but because it’s clever, or funny or lyrical, we see it as having earned its place. I think we all know when we've written a nicely turned out phrase and who wouldn't want to show that off? The problem is it means the rest of the narrative suffers and, difficult as it may be, the sage thing to do is to remove it.
I don't necessarily agree.
I think that writing has become so conformist that people are too ready to take out everything that doesn't serve the narrative, even their own voice. Speed up, get to the point, show it like a movie, raise the stakes, rush to the next plot twist.
I'm not saying dull, meandering, pointless stories should be allowed a free pass. Above all things I think the story needs to be interesting, but I also want a story told in an enjoyable way. Personally, I like those little moments unique to a particular writer even though they may go off at a tangent or are a distraction from the main storyline.
Much like how screenplays became very mechanical at one point, as though every film should aspire to be an 80s action movie where set piece follows set piece and the only dialogue is purely functional with the occasional quip, fiction is taking a similar bums-on-seats approach. Sometimes a meaningless chat about French McDonald's is just as interesting as blowing up Nakatomi Plaza.
The problem is it's not an easy task to find the right balance and many people make a mess of it and then get defensive. It’s the sort of thing where if you pull it off no one says anything, and if it doesn’t work people start quoting rules at you explaining how you shouldn’t even try.
Rather than rejecting all attempts to take a more scenic route, I think there should be room for the odd walkabout.
So, in terms of that wonderful line that doesn't belong in the middle of a tense scene, I don't think cutting it out is the only way to go. You can move it to a more appropriate spot. You can integrate it better into the scene. You can rework it so that it has some relevance to the story. You can change the structure so that it doesn't feel like it's crow-barred in. There are a number of ways to make it work with what you're going for without derailing the flow of the story.
I'm certainly not advocating you leave it as it is and try to get away with “it's literary fiction” (which is a surprisingly popular defence). If it doesn't work then it doesn't work and it needs to be changed but that doesn't mean you have to throw it out completely.
Here’s an example. A man is attacked in his home and is knocked to the floor. He looks up and notices a flower pot on the window ledge that is of a peculiar shape. Insert profound/witty/mesmerising line about pot. Then back to the fight.
Completely inappropriate. Has to be cut, right? No — has to be improved. The flower pot is irrelevant to the scene, so make it relevant. Let’s say out hero uses the pot to defend himself. But still, he’s not going to stop to compose an ode to a terracotta pot while he’s about to be killed is he? No, but in order for the pot to not seem like a convenient plant (excuse the pun) that suddenly appears, you would need to have mentioned it before for some seemingly unrelated reason. And that’s when you could have used your killer pot line.
There’s always a way to make the scene work in the way you need it to, and chances are you’ll be able to improve it at the same time.