I actually have no idea, man, but I have the exact same thing. I will stutter more around my friends and family, and appear almost fluent around strangers. I personally think it all boils down to the fact that I'm more comfortable around those people, and I don't try as hard not to stutter around them. Also, yes, I always stutter when ordering food, regardless of the situation. It's so weird. It's almost like we're the same person.