Reading through contributions to the "Practice, practice, practice" debate made me think of the time I assumed it would be easy for me to play a guitar piece I'd learned on a classical guitar (without fret markers) simply because I was now using a guitar with "dots" to guide me. To my surprise (and embarrassment) I couldn't play it. It had nothing to do with different fingerboard width or number of frets to the body - they were the same.

Looking at the "dots" interfered with my brain - I'd actually learned to play the piece with my eyes closed.

Maybe all guitars should be built without fret-markers!?