On a TV cooking show I watched this week, the Chef mentioned if more than 3 flavours are added to a dish the taste will be neutralized. The same could be said for number of colours in a design, or the number of elements in a grouping.
When I looked into it further, three seems to be the rule of thumb for the universe.
For instance, atoms consist of three constituents: protons, neutrons, and electrons, and each of these are comprised of three quarks.
...There are the Three Little Pigs, Three Little Bears, Three Blind Mice, Three Periods in Hockey, Three Strikes and your out.
To survive, we cannot exceed 3 minutes without breathing, 3 days without water, 3 weeks without food.
And, the corner stones of modern society; Rock, Paper, Scissors the Three Primary Colours, and the Holy Trinity.
Notice the grouping of three in my logo... accidental? ...or divine intervention.