A good guitar player can strum a few chords and keep a rhythm. A great guitar player will play the exact same chords and the keep the exact same rhythm but he knows when to let them ring and open them up and how to bend and fit them individually into the small spaces. He channels a particular sound or plays along with another musician. He listens to the sound he makes alone and to the sound others are making if there is more than one musician. He has the ability to hear the sound he makes but also to hear the sound of the music as a whole. He respects the level of the other musicians. In a band there are layers to music so it is his job to find his layer to create harmony. He is not embellishing the music. The music is embodying him. When he put his instrument in its case or on its stand the instrument does not stop playing, nor does he stop playing it, nor is it a break, nor is there silence. A song is being written as we speak.
You gotta know Marty!