I'm guessing many have heard this one before, but for those that haven't I believe it's relevant to this thread's title (?)...not trying to hijack the thread. Was supposedly in a book by a Blackbird pilot.
The predominant radio chatter was from Los Angeles Center, far below us, controlling daily traffic in their sector. While they had us on their scope (albeit briefly), we were in uncontrolled airspace and normally would not talk to them unless we needed to descend into their airspace.
We listened as the shaky voice of a lone Cessna pilot asked Center for a readout of his ground speed.
Center replied: "November Charlie 175, I'm showing you at ninety knots on the ground."
Now the thing to understand about Center controllers, was that whether they were talking to a rookie pilot in a Cessna, or to Air Force One, they always spoke in the exact same, calm, deep, professional, tone that made one feel important. I referred to it as the "HoustonCenterVoice." I have always felt that after years of seeing documentaries on this country's space program and listening to the calm and distinct voice of the HoustonCenterControllers, that all other controllers since then wanted to sound like that... and that they basically did. And it didn't matter what sector of the country we would be flying in, it always seemed like the same guy was talking. Over the years that tone of voice had become somewhat of a comforting sound to pilots everywhere.
Just moments after the Cessna's inquiry, a Twin Beech piped up on frequency, in a rather superior tone, asking for his ground speed.
"Ah, Twin Beach: I have you at one hundred and twenty-five knots of ground speed."
Boy, I thought, the Beechcraft really must think he is dazzling his Cessna brethren.
Then out of the blue, a Navy F-18 pilot out of NAS Lemoore came up on frequency. You knew right away it was a Navy jock because he sounded very cool on the radios.
"Center, Dusty 52 ground speed check."
Before Center could reply, I'm thinking to myself, hey, Dusty 52 has a ground speed indicator in that million dollar cockpit, so why is he asking Center for a readout? Then I got it -- ol' Dusty here is making sure that every bug smasher from Mount Whitney to the Mojave knows what true speed is. He's the fastest dude in the valley today, and he just wants everyone to know how much fun he is having in his new Hornet.
And the reply, always with that same, calm, voice, with more distinct alliteration than emotion:
"Dusty 52, Center, we have you at 620 on the ground."
And I thought to myself, is this a ripe situation, or what? As my hand instinctively reached for the mic button, I had to remind myself that Walt was in control of the radios. Still, I thought, it must be done -- in mere seconds we'll be out of the sector and the opportunity will be lost. That Hornet must die, and die now.
I was torn. Somewhere, 13 miles above Arizona, there was a pilot screaming inside his space helmet. Then, I heard it. The click of the mic button from the back seat. Walter spoke:
"Los Angeles Center, Aspen 20, can you give us a ground speed check?"
There was no hesitation, and the reply came as if was an everyday request:
"Aspen 20, I show you at
one thousand eight hundred and forty-two knots, across the ground."
I think it was the forty-two knots that I liked the best, so accurate and proud was Center to deliver that information without hesitation, and you just knew he was smiling.
It all had lasted for just moments, but in that short, memorable sprint across the southwest, the Navy had been flamed, all mortal airplanes on freq were forced to bow before the King of Speed. A fine day's work......
Pretty good speed for an old B model 421. 
