From my friends-of list, 2am_optimism is very cogent--and could easily be speaking for me--when she says:
It's a sad fact that I've become a little more distanced from that complete ability to immerse yourself in a fictional universe as I've got older. On the other hand, as I've got more discerning about the quality of my reading, whole new worlds have been opening up to me in terms of appreciation of the craft of writing.She also performs Myers-Briggs analysis on Buffy characters ("Can you psychoanalyze a vampire?"), which I point out for the sake of knowledgeable sorts like katallison and anyone else interested in fun stuff like that.
[Edited to remove my lack of fun on other subjects.]