Have you ever noticed your innate ability to detect flaws in anything and conjure up a thousand ways to improve it? Well, most of the time you just have no idea what you're talking about (Chesterton's fence; I talked about it before), but sometimes you may actually be onto something. In fact, the most effective way to come up with great ideas is to build on the ideas of others. It's even one of the rules of brainstorming at IDEO (They know a thing or two about creativity). You've heard Picasso's quote "good artists borrow, great artists steal"; I think this is more or less what he meant: build on the ideas of others.