I’ll go with Barack Obama, and include “just cheating on a spouse” in my betrayal and disillusionment. I’ve said from the beginning of his (first) presidential campaign that if he ever had a sex scandal it would break my heart.
My attitude toward Jon Stewart is more protective. I always feel like I would be devastated if anything bad ever happened to him, but I don’t think I’d be particularly concerned if he just turned out to be an asshole.
This guy. Yeah, everything I’ve read about him makes me want to just hang out with him.
Stephen King. He seems so goofy, I just couldn’t imagine he’d be mean.
I went to a party at his house once, and he was a genuinely cool guy. Nice and friendly, not obnoxious or opinionated at all. (Of course, maybe he was on good behavior since it was a party!)
Aw crap.
Seeing as how he used to be a major druggie, I’m sure he’s had his share of asshole moments, but I like to think he’s all better now. 
Dolly Parton. She has to be a sweetheart in person in order for the universe to maintain anything resembling order.
I’ve been a huge David Bowie fan since I was 8 and I’ve never heard of anyone having a bad opinion of him. Yeah, he was a huge druggie in the 70’s and he admits he was a mess and has many regrets from that time and also the Nazi salute controversy, but I believe and always heard he’s a decent guy. He’s well respected in the music industry and is known to promote new bands he’s fond of.
In a similar vein, Iggy Pop. Yeah, he’s kinda out there, but he has no ego and anytime I’ve seen him on a talk show or something, he’s always respectable, funny and very smart. I’d love him as a next door neighbor.
On the other hand, he did name his son Zowie Bowie, which is a borderline child abuse.
But Zowie Jones kinda has a nice ring to it.
nm
Evidently Duncan Jones disagrees.
Years ago my husband (then boyfriend) came to visit California from England. We arranged a tour of Warner Brothers Studios & they took us into some of the sets that were currently filming. Mark Harmon made a point to come over to our little tour group (mebbe 6-7 people) and introduce himself, shake everybody’s hands, and thank us for our interest. He was in some sort of Legal drama at the time, of which I knew nothing, but I was very impressed at his friendliness. Nice guy!
I don’t think I’d be saddened by a love affair or adultery. People and their private and romantic lives can get very complex, and I don’t really think it’s fair for the media and general public to start casting stones at celebrities for their infractions.
Criminal or violent behavior, a bizarre meltdown, or an all-around arrogant and jerkish personality would disappoint me though.
Off the top of my head I’d hate to see these in:
Ewan McGregor (who always seems like an affable guy)
and
Johnny Depp (again affable, and I’ve always liked his acting)
Mike Holmes, of the renovation show Holmes on Holmes. Yes, he bitches about bad home design, but other than that he seems like a swell guy, at least to homeowners. If he were bossy and demanding to his construction crew that wouldn’t surprise me, but if he was an asshole to other people…well, I just don’t wanna know.
A couple of the above would indeed surprise me a bit ( Michael Palin is an excellent example ).
One which didn’t particularly sadden me but who really did catch me off-guard ( I don’t know why ) was Joe Strummer of the Clash. Not that I knew all that much about him, but I always heard he was the generous punk purist, while Mick Jones was the difficult diva. But the documentary on him makes it pretty clear that despite some positive attributes ( including plenty of natural charisma and talent, as well as those flashes of generosity and kindness ), he was quite frequently a difficult prick, shitty husband, lousy bandmate, etc… I was a bit taken aback.
I have personally met and spoken with Ronny Cox on two occasions, and he is extremely sweet and charming. If there were to be some scandal involving him, I wouldn’t believe it.
Even if I was informed through the media that my biggest hero was a grade A jerk, I would take it with a grain…nay, a kernal tonne of bushels of salt. Knowing the source.
If you take episodes of every humans life, there are instances of asshollery that I’m sure would be out of proportion to their relative being. I can forgive a lot, in other words. And I am not likely to take biased accounts for face value… lotta money and bigotry involved in building up celebrities and shootin’ them down. I am not tied to the fickle masses.
I’d be truly disappointed if I found Lemmy from Motörhead to be a pretentious dick. (Of course, he’s very recognizable, so I probably wouldn’t go up to him in the street, but say I’d have an appointment or a beer with him or whatever.) Anyone seen Lemmy the Movie? That guy just seems so laid back.
And Hugh Laurie. Career actor, funny, charming, very smart, jazz vocalist, best friends with Stephen Fry - and apparently happily married for over 20 years. He seems like the British equivalent of Jo Nesbø. (Albeit I can never get used to seeing him walking without a limp and talking in a British accent in interviews these days.)
Bowie was attempting a literary tribute to J.D. Salinger with that name (think “Franny and Zooey”).
But the kid hated the name and started going by “Joey” as soon as possible.
I had exactly the same reaction. While I was watching the documentary I got a phone call from a friend. I told him what I was watching and said, “he’s really coming across as a total prick.” Then I paused for a second and said, “Who would have guessed? A punk rocker who’s a total prick!”
I guess it’s just not something I had thought about too much, but to be part of the punk scene in London in the '70s (and early '80s) and succeed to the level that the Clash did would pretty much require you to be totally driven and focussed on success - conditions ideal for prickish behavior.
To address the OP, I agree about Michael Palin, but really no-one else springs to mind.