It's always a messy business looking too far beyond the facades put up by our favorite celebrities and icons. We love them for their work, for what they represent, but their real lives, personalities, foibles, struggles, failures - and in some cases, crimes - often paint a picture that conflicts with what we want to believe.
Robin Williams, funniest man on the planet, knew darkness so deep it was always on the verge of swallowing him.
I never cared much for Kurt Cobain's music, but his suicide in the midst of all his success shocked me.
I was angry at Hunter S. Thompson when he shot himself, although I never met the man. Philip Seymour Hoffman died of a stupid drug overdose even as he was cementing his place as the actor's actor of his generation.
In those instances, they left behind a body of work that stands apart from their real-world ends. Those ends also inform the work that they did, and add a layer of richness - the darkness in some of the characters portrayed by Williams and Hoffman, for instance, or Thompson's informed, fatalistic cynicism.
Then there's Bill Cosby.
From what I've seen of the sexual assault allegations against him, the cases would be hard to prosecute in court under the best of circumstances. Given that the incidents happened years or decades ago, there's probably nothing the criminal justice system can do.
But Cosby's standing and legacy have been shattered, because this knowledge of alleged misdeeds does not add a layer of meaning.
It adds a layer of creepiness and disgust.
It's especially jarring because Cosby always represented warmth, trust and comfort. In the '80s, he was the face of wise fatherhood on "The Cosby Show." We listened to his comedy as a family in my house; the Noah bit, Chocolate Cake for Breakfast, the Water Bottle, his dissection of how he burns up clutches.
Much has been made of this bit from an album titled, now ironically, "It's True! It's True!" Cosby goes on about Spanish Fly, the aphrodisiac of legend.
He tells a tale of 13-year-olds telling tales. One says, "There's this girl, Crazy Mary. You put some in her drink, she'll go [makes crazy drooling zombie noise]. Yeah, Spanish, oh yeah, it's really groovy, man. Spanish Fly is groovy."
Cosby continues: "From then on, every time you see a girl ... you go to a party, see five girls standing alone. 'Boy, if I had a whole jug of Spanish Fly, I'd light that corner up over there!' "
The audience is laughing, and in a vacuum, it's easy to see why. It's a story about adolescent boys noticing girls like they haven't before, and swapping urban legends about how to get to something they don't really understand.
The joke goes on to when Cosby was on "I Spy," and filming took place in Spain. He and his co-star, Robert Culp, apparently knew all the same Spanish Fly stories and hoped to pick up a supply of the drug while there - but they were disabused of that notion by their cab driver, who asked them if they had any "American Fly."
That's classic Cosby - the innocent, bumbling man (even if that innocent, bumbling man is trying to be up to no good) being had.
But now, it sounds too similar to his alleged behavior over the last 40 or so years.
It's not funny anymore.