I've written over 300 songs and all of them are ''ear pleasing''. The real number is limitless. There's a never-ending well of inspiration out there and it is made up of more than 6 notes. It's those notes, the chord, the key changes (very important, but top 40 doesn't know how to do it), Rhythm, Harmony, arrangement, production, etc. which all do wonderful things to camouflage what's been before and make it sound like it's being heard for the first time.