If I had a dollar for every time I have heard this statement in the halls and corridors in the advertising agencies I have been in all over the world, I could retire, easily, today.
It is a statement you start hearing at university/college and it never seems to lose momentum at all. It is possibly the most guiding principle of advertising. Consumers do not have time to figure out a complicated story line or concept that is so deep you would need a submarine to understand it. So, Keep it simple is the motto. But as advertising is a place where creativity loves to play with words or phrases and just in case the three thousand times you hear it is not enough the word stupid is added on to embed the message.
But only in advertising would you find such a cutting sentence turned into a loving and emotional acronym. As the acronym for Keep It Simple Stupid is simple KISS! Have a creative day.