Let's face it--the majority of the time fans only want a photo with a celebrity so they can prove to their friends that they actually saw or met that person. And I'd be willing to be the most of the time they don't really care who it is, they just want to be able to say they met a celebrity.
Maybe I'd feel differently if I lived in a small town somewhere in, say, Nebraska. But I live in southern California and I've seen a lot of celebrities in my 51+ years; mostly actors, but a few musicians. And unless it happens at some sort of event or paid appearance where they're supposed to chat with the fans, I never approach them; I might nod or wave hello if I happen to catch their eye, but nothing more intrusive than that. As Michael Bergeron stated above, they're not there to "bend to my whim", they're just people going about their day, and I feel I don't have the right to be rude and disrupt that just because they're "a celebrity". Believe me, there have been times when I've wanted to break that "rule", but manners and respect for them as a person won out every time.
That said, I can completely understand Louis C.K.'s perspective on the matter; I'd much rather have a conversation with someone than snap a relatively meaningless photo with them.
