The KISS Principle actually has nothing to do with the band Kiss. I Just used their logo to help you remember the concept.
From Wikipedia;
KISS, an acronym for "keep it simple, stupid", is a design principle noted by the U.S. Navy in 1960. The KISS principle states that most systems work best if they are kept simple rather than made complicated; therefore, simplicity should be a key goal in design, and unnecessary complexity should be avoided.
Now, I don't like to go around calling people stupid, so I modified the acronym to stand for: