When we (Mum, dad, and moi) moved back to Toronto, when I was 18 (from Montreal) my mother suggested I take some REAL lessons from a "serious" guitarist. He was a veteran studio pop player and a very nice man.
I went to see him and he didn't even ask what I'd learned or accomplished in my three years of playing before plopping the sheet music to "Red River valley" in front of me. He asked me to start reading the melody line (I couldn't read at that time) and I gave it a shot...slowly. After an hour he still didn't know what I COULD play already, and I was pretty frustrated. Simply put, he was going throuh the motions without a hint of personal interest.
When the "lesson" ended, I summoned up the courage (I wasn't the outgoing blabbermouth I am now, in those days) to simply play something for him. I played Merle's "Blue Smoke", and "Cannonball Rag" and Chet's "Windy and Warm". (put 'em into a two minute medley)
When I had finished, he frowned and said "You have to stop using your thumb"(I think he meant BOTH right and left hand). I replied, "how do I keep the beat going, then?" He said "THAT'S WHAT THE BASS PLAYER AND DRUMMER ARE SUPPOSED TO DO"! He apparently didn't feel that "solo" guitar (other than classical) was even a valid form of music.
Almost thirty years later I bumped into him at a concert I was doing, and we started jamming. He's still definitely from the "old school" but he played "Bye Bye Blues" in "Merle" style. Gawd I was tempted to tell him to "get rid of those thumb chords!"... but I didn't. Takes a while I guess, but folk music had caught up to him!