No, I remove animal ones (horses, ruminants, exotics, but mostly dogs and cats).
For me it is easier than what others have said. I look for the atlanto-occipital joint, cut through to the cord, and then sever the joint.
Not too hard, and quick, if you have leverage and a sharp knife. But to be honest, the animals are already dead, and deplucked (meaning no trachea, esophagus, muscles, or any other tissue).
Blast you, now I’m curious about how the human way works…
As much as I’d like to (legally, y’know, like that of a cadaver), I’m afraid I don’t have the people skills and love of chemistry for med school, and that’s really the only avenue I can think of where people get to do that stuff.
Working with doctors for many years, I can say that it doesn’t seem like people skills are a pre-req to be one. 
Not something I’d want to put on my resume :eek:
Well, not all the time. At some points she posted.
Well, think about the guillotine, a machine specifically designed to remove human heads. That puppy generated some force!
From the guillotine article on Wikipedia:
Yeah, I’d say that if even a trained executioner couldn’t always do it so well, it would be pretty hard for some crazed lunatic in the cramped confines of a Greyhound bus.
But apparently not too hard for QtM to do with a good scalpel, good light, a good work surface, and a compliant decapitee.
To quote Emperor Palpatine, “To feel the power of the hate flow thru you…” 
There’s a difference between slicing and chopping. Executioners that chop with a sword or axe are trying to do it in a fraction of a second, and that can be difficult. Slicing with a sharp blade is considerably easier. I forced myself to watch nearly all of the terrorist execution videos (see above reason) and they took at most 90 seconds, most under 60.
Graphic TMI:The reports about the interior of the bus being covered in blood are no exaggeration. The heart keeps pumping during the entire grisly act and blood pours everywhere.
So if you’re so inclined, it can be done rather quickly.
Zing!
While I’ve never done it myself, I’ll back up those who have said it doesn’t take more than a minute, unless the Iraq videos have been edited, which is very possible.
As volleyballer said, my understanding is that a good piece of Japanese steel could lop a head in one swipe pretty easy, although a three foot blade with a full swing is a lot differnt than a shitty rambo knife on a bus.
(I know that the exploits of Japanese swords are greatly exagerated in lore, but I think taking a head off with one is pretty well documented)
Does it have to have been dead first?
Actually, in her contribution to the old How can I weigh my own head? thread (the 2nd post), she only appealed to her experience in weighing heads where it had arrived decapitated.
Now those are an adjective and a noun that I never thought would be used together
All I was gonna say is, that’s going in the list for the next time someone wants new user name suggestions.
One thing to keep in mind is that medieval executioners were not selected for their ability to get the job done quickly. An execution that required several attempts to take off the head was preferred to one that got it over in a stroke, because it would be more painful and because it made for better theater.
I sharpen knives to the point that they will shave hair. It would take no effort at all to cut straight through a turkey with a few strokes of a long knife.
And as a side note, if I see a group of Mohammed’s unholy servants coming at me with a knife the last thing I expect to hear is Allah Ackbar spoken in a very high pitch. I intend to go down with someone’s nuts in my mouth.