Hi Guys,
it's not the speed, it's the apparent speed.
Right now everybody in the latitude of North America is travelling due East at ~600mph along with the planet while not moving out of their chair.
And most of us have looked out of an airliner's window at the ground going by and know you are going ~500mph but it sure don't feel like it.
For me, the fastest speed sensation was going mebbe 12mph hanging off a trapeze on a racing dinghy.
Most hazardous speed? Betcha not more than 2mph falling down the basement stairs underneath the kitchen stove I was attempting to move down there.
Thought I'd broke my leg for sure.