Playing God is terrible, when you're supposed to die, you die...other people are not supposed to make that decision for you.
People with extreeme cases of pain, I could possibly deal with; The killing of criminals, I could possibly deal with (though that would be hypocracy on our part).
I'd assume you're right blike, when people actually see what "hell" is like (not that they feel, or experience it themselves), and how much pain individuals go through, why not end the suffering? Seeing as how I'm partially religious though, I cannot agree fully with Euthenasia.