Three is the magic number

In the words of David Frost: ‘Hello, good evening and welcome.’
Q: Why is it that repeating something three times is effective?
A: Because our brains love the pattern of three.
It's true, place three items on your mantelpiece and see how nice they look.
Three is so effective that by simply repeating the same word three times gives impact. Education, Education, Education. And that’s the truth, the whole truth, and nothing but the truth.
Sports use the power of three. Athletics and swimming begin with a version of ‘On your marks, get set, go!’ And football matches end with three blows of the referee’s whistle.
The recent election debates as reveling in the dynamic of three, as the third cog provides all the drama. You see, three’s a crowd and that creates conflict.
Stories love conflict and use the magic number all the time. From the nativity with its three kings (and Christianity its holy trinity), to the three bears, blind mice, little pigs and musketeers. Three characters are all you need for a ratings busting soap opera (they adore love-triangles) or lauded movie (e.g. The good, the bad and the ugly).
But it’s not just drama that loves the number. Jokes are often created with a set up, anticipation and punch-line (e.g. The Englishman, Irishman and Scot).
And quotes are made memorable by its use. We are taught road safety with the mantra ‘Stop, Look and Listen.’ Then learn to drive with, ‘mirror, signal, maneuver.’
Remember these?
“Some people are on the pitch, they think it’s all over, is it now.”
“I came, I saw, I conquered.”
“Friends, Romans, countrymen.”
“Lights, camera, action.”
“Blood, sweat and tears.”
etc, etc, etc.
Perhaps most importantly, is its use in novels. What would they be without a beginning, middle and end?