I overheard the pawn shop guy telling one of my niblings never ever to paint a guitar, it makes it worthless. But I couldn't tell if they meant resale value or playability - is there some musical reason never to paint a guitar? Repaint, that is, if it's one color and you don't like it, can you paint it another? If not, how, exactly, does it ruin it... prevent the nice tone through less vibration, or what? Does it matter if it's an acoustic or electric?