Music Theory

I work at the Cinema/Bar in downtown Athens. Today behind the bar we got to talking about some very basic music theory issues, and with access to Wikipedia I thought we surely could quickly resolve some basics. All we were talking about was this: As the comedian/TV actor Jerry Seinfeld might put it, What is the deal with having sharps AND flats? Why not just have one or the other? Or why not embrace a system of music notation that does away with them entirely?

But looking around on Wikipedia for answers, I only found more and more questions. Music theory seems so intimidatingly large, strange, and arbitrarily-defined. Also: In being this way, music theory seems very similar to political theory or pretty much any other body of knowledge you might care to name. I want things to keep the simple and graspable look they have from far away, but as I come closer I see it's not the case.