I'm very critical of the music I listen to. Whether its lyrically, or instrumentally. I have a wide spread collection of music just for listening. I have friends and groups at my university that share music we find not necessarily to critique the music in any meaningful matter, but to share the experience of listening to the music. I would say that listening to good music is a hobby. Eating food can be a hobby. Food critics are very critical of the food they eat, but their jobs are simply to eat different foods, and explore taste. When I take a shower there is really only one way to take a shower, but there are an infinite number of ways to experience listening to music.
The only way I determine what good music (Music I like) is by listening to music all the time which is what I do. Listening to music is a very active part of music, and really isn't passive in any sense. If you are passively listening to music you really aren't listening to the music, you are just hearing it.