Books: Time seems unrelenting enough that I'm not interested in reading tens of books about bands whose music I don't already love. Thanks for the suggestion, though.
I'm related to a serious (professional and quite successful at it) musician, with an incredibly solid background in jazz, and he can't explain why he's so head-over-heels for the Beatles. He's tried, to no end, but it usually goes along the lines of, "they were just so...perfect. Every sound, every little thing, they just had something that nobody else has." Plus all the standard stuff of, "they're incredibly influential!", which thing I don't deny, though I don't find it sufficiently satisfying a response, either. I don't mean to trivialize influence, but influence isn't, by definition, inherently good. For all I know, we'd have better music now if it weren't for them. (The argument for that is easier than it might be for some other influential songwriters, but getting into that isn't my intent.)
Social bookmarking: I asked why I "should," not why I "have to." Important distinction. Mine was an invitation for smart people (which tend to be in longer supply on this site than on many others) who tend to have reasoned tastes to try to explain to me why they're fans. Saying the records are "fabulous" is fine, but: why? Say it's wholly a matter of taste, and I'm OK with that, but then I don't understand why so many Beatles fan act like I'm the antichrist for not being madly in love with their music. It happens pretty often that, in this pop culture, someone expects me to love some Beatles song/Cirque show/something as much as they do, and upon the discovery that I don't, they usually presume that I'm some kind of insane. Which seems odd, if it's all just a matter of taste. But if it isn't, I'd like reasoned answers (and this thread is not without some good contributions).