Mary had a little bike,
She rode it on the grass.
And every time the wheels went round
A spoke went up her -
At which point I stopped, and the audience laughed (luckily - I'd have been scuppered if there had been silence). Why did they laugh? I asked them. The answer was because they knew what word was coming next - and in fact one lady helpfully mouthed it at me just in case I hadn't known. But the missing word isn't intrinsically funny, so why the laughter?
I'm sure there are lots of complicated psychological reasons why the omission of a mildly rude word can get such a reaction with a group of adults, but what I was using it for was to demonstrate that the audience was both willing to do some work - ie supply the missing word - and enjoyed the process. In fact, they enjoyed supplying the missing word far more than they would have done if I had said it.
When we're writing we can forget that the reader wants to work, and will enjoy their reading far more if they have to make an effort. That's the basis for show, not tell. We show the reader a situation, the reader does some work and deduces for themselves what's going on. It's much more effective than telling them exactly what's going on. Tell us that Evangeline was nervous, and we're bored. Show us Evangeline's sweaty palms or bitten fingernails and we're delighted to deduce that she's nervous.
Make the readers do some of the work, by showing and not telling, and you've got them hooked on your story.