Living in southern California, I get the opportunity to see well known folks from time to time. In all honesty, I don't pay them much attention....
I did, on one occasion, hold the door open at a Starbucks for Kathy Ireland. I was going in for a cup early in the morning up in Santa Barbara and she walked up behind me. I held the door open before even looking back. As she passed, she kindly thanked me. When I got in line behind her, she offered to let me ahead of her in line since I had held the door. I did not recognize her at first, because she was in sweats and no make-up. I just thought she was a pretty girl...

I let her stay ahead of me and heard people whispering about who she was. Once I got my coffee and was leaving, she was walking out in front of me and held the door open for me....lol Not much of a story...
On another occasion, I saw Jamie Lee Curtis shopping for furniture in downtown Santa Barbara. Did not talk to her. I have always liked her, but I am just not one to bother folks.
I did get the opportunity to hold a short conversation with Don Rickles on a flight to Vegas once. I was reading a book and he sat down in the seat across from me. He commented on the book (he had read it too). We talked for 4-5 minutes and I told him that I had always enjoyed his comedy. He said "thanks" and that was about the end of it....
I have had several other opportunities, and have actually worked on some custom homes for a few. Being one to enjoy my own privacy, I have a tendency to just ignore my surroundings. My wife laughs at me, but I figure they are not any better than the rest of us. I truly admire some of them, and envy their talents, but don't really get all that excited.... Plus, I am not a great conversationalist and would never know what to say if I did want to meet someone.... :unsure: