Howard - I think guitar lends itself to playing by feel much more than some instruments. One of the best guitarists I know sometimes struggles to find chords if they're written down in front of him, and struggles even more to explain what he plays if it's not written down ("it's... D plus a bit"). Coming from wind instruments, one thing I like about learning (English) concertina is that the notes are right there - you want an A, you press the A button, you get an A. It makes it easy to take chords off the page ("would a D6 give me the sound I want?") but not so easy to noodle around ("would I get the sound I want if I put this finger here instead of here?").