The Rule of Three
Since I use it all the time and not everyone has been exposed to the concept, I will take a moment here to explain the general concept of the Rule of Three. I have been using it soo long, and it is used so often in business contexts that I take for granted that people just know the Rule of 3. It just works.
TL;DR - You sound more structured and confident. Forcing yourself to use three points provides a structure to your presentation of your thoughts. It keeping keeps you focused, it forces you to be concise and it hits home with executives and interviewers. Give it a try, I promise it works.
The Science
Alan Baddeley conducted a long series of studies on human memory and information processing. He concluded that you can remember about 3-4 things (for about 20 seconds) and then they will disappear from memory unless you repeat them over and over.
For an interesting discussion on the topic, check out this article.
McKinsey Consulting
The Rule of 3 is a rule of thumb for executive communication. Whenever you’re trying to persuade a senior person to do something, always present 3 reasons. Not 2, not 4, but exactly 3. Ameet Ranadive shares how he learned the Rule of 3 from consulting and concludes with three key points:
Get their attention
Forces Choice
Sound more structured, confident, and decisive
From the Real World
It simplifies your thinking. Three is the least number of items needed to make a pattern and the best evidence seems to come from our natural world, where evidence of groups of three seems to exist in all domains:
Stories: Three Little Pigs
History: “Life, Liberty & the Pursuit of Happiness”
Physics: Newton’s Three Laws
Writing: Three-Act Structure
Slogans: Snap! Crackle! Pop!
Photography: Rule of Thirds
Consultants: Three Key Things