It's a small world and it only gets smaller the longer you stay in the industry...

Since I fly with the same person every trip (and often carry the same passengers), I'd say I run into somebody I know every flight... but that's not what you mean, huh?

I do run into old college friends and former coworkers pretty regularly- almost every trip I see somebody that I know in an FBO or airport lounge/terminal. I've also had several instances at the airlines where people I've known from high school or wherever have been on my flight. In fact, I once had my dad on a flight (he travels extensively for work), and we didn't even realize it until after we had landed and I was standing at the door saying good bye!