KISS principle (Keep it simple, Stupid.)
It was Albert Einstein who said; “If you can’t explain it, you don’t understand it well enough.” Though it is often mis-reported as being; “If you can’t explain it to a six year old, you don’t understand it well enough.” What Einstein was driving at was a particular application of “keep it simple, stupid”.
From scientific concepts to products the end-user doesn’t care how clever the creator or designer of something is. They care about being able to take that person’s output and make it useful to their own lives. The simpler the explanation and the simpler the product, the more likely it is that the output will be useful to others.
The phrase; “keep it simple, stupid” is thought to have been coined by the late Kelly Johnson, who was the lead engineer at the Lockheed Skunk Works (a place responsible for the S-71 Blackbird spy plane amongst many other notable achievements). It is worth noting that Kelly’s version of the phrase had no comma and was written “keep it simple stupid”.