I did meet Dolly Parton and Porter Wagoner years ago (in about 1972 or '73--I was in high school) for a minute after a concert. We got their autographs, and Dolly told me she like my dress.
When my daughter was in line at a cell phone place, she saw Tony Hawk in line. I met his mother in line at Palomar College (San Marcos, CA) several years ago (he was just gaining some notoriety at that point and she was telling me about him--definitely a proud mom! She was nice).
For a near-miss--my dad owns and manages a sewing machine/vacuum cleaner store in Escondido, CA and was in the back doing paperwork one day. He heard a familiar voice, but the person was gone by the time he got out front. It turned out Tom Selleck had come in to buy some vacuum cleaner belts or bags. My dad asked the kid who had served him why he didn't come back and get him so he could meet him, and the kid said, "You were busy." Tom Selleck and his brother had just bought a mall there not long before that.