Well, shoot me for all the times I've struck up conversation with people I run into on a daily basis -- those I know well, don't know at all, recognize, or after talking a bit, realize they know a friend of mine or I a friend of theirs. IMO, dont be an a-hole, but be a civil human being talking to another human being in your approximitity. Katy isn't untouchable, she's very human and more relatable than most, lol. If she sitting down in a restraunt eating (or something more private/personal)... that's different. But if she's... walking down the same side walk, crossing the same street as you... be friendly and open you're mouth to say HI! Spread the love! LOL IMO, of course.