I do on a regular basis, both because of where I live, and because of what I do for a living. Most celebrities I've met are assholes, but there are exceptions to that rule. Because I've been doing what I do for years, I do not get excited about meeting any celebrities.
Here's a funny one. I was in line at a local Jamba Juice with my daughter, standing behind a tall gentleman with a familiar-looking bald spot and two kids (boys). I sat there, wondering where I'd seen that bald spot before. I sudddenly realized that it was Pete Sampras, with his kids, in line in front of me. It was entertaining to me, but I didn't bother him or engage in any conduct that would indicate that I knew who he was. We both went our way, and a few minutes later, i told my daughter who the tall guy with the bald spot was.
Pete Sampras has put on some muscle since his Wimbledon days, and looks better than he did when he was ranked number 1.