Three is also about creating balance.

A sentence with two options or pieces of information seems incomplete. The reader perceives an "either/or" position inherent in writing that is structured this way. Without a third element, these options seem to be at odds with each other. Three replaces this adversarial tone with choices, fluidity and completeness.

"This porridge is too hot. And this porridge is too cold! Ah, this porridge is just right!" – Goldilocks

When faced with two extremes – black versus white, beginning versus end, or optimism versus pessimism – three provides the gray, the middle, the realism. Three can turn "either/or" effortlessly into a continuum by drawing a line between two extremes and opening up the possibility of all points in between.