I tend to differentiate the card show 'business' meeting from the casual meeting. Among the casual meetings:
Jim Brown: I ran into him--literally. I was leaving my room at the hotel in Cleveland one a.m. before the National and wasn't looking and banged into him. Like hitting a brick wall. I'm 6'3" and was about 240# at the time and I was the one who moved. I excused myself then realized who it was and said "Hey, you're Jim Brown...but you probably know that already." I chatted with him briefly. As I recall he was in town for the show and the HOF induction at Canton. I think it was for Gene Hickerson that year. He was also great at a show I went to; when I asked him to sign a 1960 Topps he asked why I was getting such a good card signed, I told him he was the best ever and I am collecting signed cards of the GOATs, and he seemed really pleased.
Luke Appling: back in the autograph early days he was a free host signer at a local show. I gave him this card to sign. Not only did he personalize it, he told me a story about the uniforms, that they were thick woolens and absolutely miserable to wear in the summer
I once got backstage at the Academy Awards (family connection) rehearsals and decided to hustle some autographs:
--Johnny Carson: great guy. Not only signed happily but was cracking jokes the whole time.
--Gene Hackman: kind of a dick but did sign.
--Cheech and Chong: awesome. So friendly that if they'd had a J I think they'd have offered to share it with me.
--Ricardo Montalban: "Khan!" was very cordial and classy.
--Christy Brinkley: really nice and my god was she amazing to look at.
--Roger Moore: An English gentleman.
--Sly Stallone: I'd seen him around LA a few times and he was always nice to fans. Signed for me and was nice about it.
The one time I became a star-struck babbling idiot was in a bookstore. I was leaving and heard an unmistakable voice asking the clerk for a book on Voltaire. I wasn't even going to approach but my wife encouraged me; she said he was alone, no one was talking to him, and I'd regret it if I didn't. So I did. I got complete verbal diarrhea and went on about his charity contribution for a school where I was on the board and some other stuff. He was really great about it. I had the autograph made into a custom card:
I grew up on Monty Python; I even made my parents take me to their live show in NYC when I was ten. So this was the best celebrity meeting I've ever had.