After reading this comment out to Rick, he mentioned 'so you're applying this to a group rather than individual opinion' - indeed I am. But it could apply on a personal level too - to tie it in to your example: 'I like Joan Baez's clear voice' could mean the listener likes the way her voice resonates in comparison to the backing music, while 'I like Liz Mitchell's clear voice' could mean her enunciation or the way it sounds like she's speaking down a tube directly into your ear or whatever. Same reason + different interpretation = cause for many arguments & resulting division!