Originally posted by Josh Redstone
if that is how it works, then how is it that those Jazz guys make their songs so catchy?

Many jazz songs are not written by making a chord progression and making a melody over it, but rather from making a melody then fitting a chord progression underneath it. "Take Five" for example... chords were an afterthought. Many hymns are like this too. "Amazing Grace", for example - what's important, the chords or the melody? The great songwriters make a melodic hook and then write the chords under it. That's why many popular songs have a super-simple chord progression - it's the melody (sung or played) that's important. Another song just came to mind - "Sleep Walk". Very catchy, due to the melody, not the progression (which is just a I, vi, IV, V).