Portillo Seconds From Death - How to Kill a Human.

[Mentor]

The most humane way that it's been done in history is the guillotine (proven), as it doesn't miss and it's very quick. Just very gory and people around it don't like it much. Firing squad also effective if they do it right. Seems pretty obvious to me but would it not be possible to make some sort of mechanism whereby a person's head is locked in place and a bullet put through the correct part of the brain without fail?

Meh, most the humain ways dont look very humain, and its really all about how it looks rather than how much suffering they cause.
Why do you think they use the electric char and lethal injection when the guillotine and hanging work much better and are painless. Hangings useually out for much the same reason as the guillotine as examplifed by saddams hanging, dont time it right you get a flying head. Which for some reason people seem to equate with more suffering, dispite the fact its just as quick and painless as if it was done right "/
The real problem is, capital punishment in general, just isnt humain. Getting nicer ways of killing people doesnt really solve the problem of you killing them in cold blood when you use it.

[FlyingJesus]

Bring back gladiator fights