Melodic Frustrations!

There is something that haunts me about melody. I've pondered how it is that some melodies tend to grab me while others didn't even seem to put a dent in me for years. I liked the melodies and lyrics with weird and interesting words (Jason Molina of Songs; Ohia is great at this), but have stayed away from melodies that wouldn't push me to hum them later. There is something to that which I can't figure out.

How does a person even create a melody? After 18 years of playing guitar and studying music, I still don't know! Melody is just one of the most mysterious things about music to me. It's also the most identifiable variable to the Library of Congress. The copyright office considers melody and lyrics to be the two identifiers as to an assignment of an original composition's copyright. Not chords!

It's how people come up with melody in the first place that boggles me. Is there some magic formula?

Nothing like public displays of creative frustration.