I like the guitar analogy, being a player myself, but chess is markedly more difficult in one important respect: feedback. To get feedback on how well your musical skill is progressing, you have your own ears, or perhaps a cat or dog that one day stops running out of the room when you begin to practice. My cat will now actually come into the room and sit by me when I practice, so I figure I'm making progress :-)
With chess, to practice you need another person, and not just one, you really need a club with several players of differing abilities. Only by being in a club will you get the feedback you need on how well your chess is progressing.
Haha, you're right! And here I was thinking to myself that it's easier to get feedback with chess because what could be less ambiguous than losing or winning a game?
But you're right. Not just the whole piece, but with every note you're getting feedback. In chess you can win after many mistakes, and even after analysis there may be many hidden mental errors, lines you missed, etc.
True. Love for the game itself is probably the single most important factor for improvement, and strangely not often mentioned (at least in my experience).
A quote comes to mind:
"I love all positions. Give me a difficult positional game, I'll play it. Give me a bad position, I'll defend it. Openings, endgames, complicated positions, and dull, drawn positions, I love them all and will give my best efforts. But totally winning positions I cannot stand." - Jan Donner