Not sure how related this is, but one musical habit I've seen become an obsession to a detriment is the rating of music. I followed this one guy on Rate Your Music - someone many of us know quite well whose username rhymed with nix o' dock - who got to a point where he was rating a hundred items a week (albums, songs, etc.) He eventually stopped and basically said, "It got to the point I cared more about rating music and saying I knew of one more band than actually enjoying said band."
That's a harmful, obsessive place that can really hinder one's enjoyment of anything, really.
Sounds understandable. I can't imagine being a rater/critic of something I truly enjoy and love. I feel like the whole process would destroy my enjoyment, having to look at things more objectively and not let myself become immersed in the actual music.
I'm also glad that, after my initial years of 'discovering' prog rock music, that I leveled out and realized that there were some bands I just didn't like or could really get into, and after I saturated my ears with enough prog, I knew what not to listen to anymore, or I just stopped discovering new bands. I fell in love with a core group of bands that I decided to learn and listen to up-and-down, front-to-back. Do I regret not being able to get into other bands in the last few years because of that? A little, but I have made some newer discoveries in the last 2-3 years (like Anathema, Riverside, Moon Safari, and a few others), but I still can't get into some of the older 70's prog bands that I missed out on in my formative years of becoming a prog head (like Van Der Graaf Generator, Gentle Giant, Camel, and many many more).
I guess one could say I know what I like and I like what I know.
-Marc.