I've written two books on theory and fretboard logic. I know the instrument in and out and I know the easiest paths for a student to reach their goals.
Everything. People, the progress that they make and the humorous times we have .
I took guitar lessons from Dave for a few months while we both lived in the same area. His lessons were what I missed most when I moved away. He is a tremendously good person and just amazing at most things music-related. It was a real pleasure being taught by him and would seek him out in a heartbeat if I ever moved to Denver. As great as it is to just be around him, what's most important is that he has a great ability to teach and inspire.