Honoring or Annoying?

Here is the question: If you see someone famous doing normal everyday stuff is it an honor, or an annoyance to go and ask them for an autograph or a photo.
I understand that there are time where famous people expect to give autographs, and I am sure it is honoring when people recognize them. But I have to imagine that there are times these people are just out doing their stuff and it has got to be annoying for people to constantly be bothering them for autographs.
Today I went to the Sprint store to pay my bill. I walked into the store with the kids, and after talking to the employee I glanced around at everyone else in the store. There was only one other couple in the store. It just happened to be Pittsburgh Steelers quarterback Ben Rothlisburger and his girlfriend (who is apparently also famous). Now Ben is famous throughout the country, but here in Pittsburgh he might just be the biggest guy in town. I wanted to get his autograph, I wanted to take his picture, and I wanted to introduce myself. But, I didn't do any of those things. I might have asked him if I had my real camera, or if I had anything great for him to sign (like a hat or jersey). But more than anything I decided the guy should be able to go out, and just be normal without anyone bothering him. I am kicking myself a little bit now, but I hope he had a good day. Oh well.