The rule of three pretty much means that three is an awesome number. Three feels natural and complete. And I'm not the only one who thinks so.
And if Schoolhouse Rock wasn't awesome enough, do any of these sound familiar?
Goldilocks and the Three Bears
The Three Musketeers
Three Blind Mice
The Three Stooges
The Three Little Pigs
Three Billy Goats Gruff
Three Little Kittens that Lost Their Mittens
The Three Caballeros
There are three feet in a yard
Things come in 3D!
Three wise men
The three-act structure
The third time's the charm.
Reading, writing, and arithmetic.
There are three primary colors and three secondary colors
Three-legged races. So fun.
Three french hens
We Three Kings
There were three Bronte sisters
Rock, paper, scissors
Three witches in Macbeth
The three-piece suit
Ready ... aim ... fire!
"Three shall be the number of the counting, and the number of the counting shall be three!"
Bacon, Lettuce, and Tomato sandwich
A long shot in basketball is worth three points
Lights, camera, action!
Triangles are the strongest shape
On the count of three ...
On your mark ... get set ... go!
Scrooge is visited by three ghosts.
"A cord of three strands is not easily broken." -Ecclesiastes 4:12
And, of course, the trilogy
So, now that I've proved to you just have awesome the number three is, let me say something a bit more useful. This is one of the most simplest storytelling devices known to man. Three is the minimum number to create a pattern. It's also the most popular pattern for telling jokes and stories. The first two items build tension, and the third item releases the tension and often incorporates a clever twist. You may see how this is familiar when you think of things like The Three Little Pigs. If the first pig and second pigs were smart enough, it wouldn't be much of a story, right? It's often the third pig or brother or attempt that gets it right. It takes three tries to beat the clock.
Threes are so ingrained in our culture, people expect them. So maybe if you notice you've got too many threes in your story, cut some out and save them for the most important things. One of my writing quirks is using the triplet. For example: I stood up, walked to the door, and opened it. I do this so much, I have to go back in my rewriting and change many of them so that I don't it.
I just like them so much!
The point is, when things come in threes, they are funnier, more effective, and super-satisfying to the reader. Now, they can be considered a stereotype too, so be careful to make your threes unique. But using a three is a great way to make your writing stick with your reader. So if you have something important or significant to say, consider working it into a three.
Take a look at your manuscript. Do you have any threes? Too many threes? And, did I forget any famous threes in my list?