Calamity/misadventure?
One of those straight-down plane crashes would do the trick nicely. Not a glancing-blow crash-landing kind of thing where some people survive with grievous injuries, but a vertical impact at several hundred MPH where there’s nothing left larger than a few inches. Once you’re past the fear over the ending of your life (think Jeff Bridges in Fearless), the actual snuffing itself would be painless; your body and brain would be absolutely obliterated before you’d have any chance to perceive any pain signals.
Self-termination?
I’d go get a giant garbage bag full of argon (TIG welder in the garage); lie down in bed; insert head in bag, tape snugly to neck; and breathe normally. Pass out painlessly, die from asphyxia before CO2 builds up to uncomfortable levels.
Benny Hill once told a story of a monarch of a country where the women were… BIG (said with appropriate hand gestures). The king had a whole bunch of wives - big ones, of course. He was a little withered up old thing, about thirty. One day, he got stuck in a revolving door with a couple of his wives - BIG ONES! - and he was massaged to death. It took the morticians days to get the smile off his face.
*
(Hill’s pronunciation of “massaged”, with the emphasis on the first syllable, made this anecdote memorable.)*
Steven King once suggested that most of us would prefer to die at age 90, after a wonderful meal, a bottle of truly excellent vino, and a really super lay. (He went on to observe that no one really wanted to experience being slowly crushed under a truck, with cold and dirty oil dripping from the crankcase on your face - but then that’s King for you).
My dad always said he wanted to be shot at age 90 by a jealous husband - and to be guilty.
Suicide . . . something quick and painless, and not involving fire or water.
Seriously, I imagine at some point in my later years, my various medical problems will catch up with me, and life will no longer be worth living. Especially if I have mental impairment, I will live it up as long as I can, and then end it all. I saw Alzheimer’s turn my father into a vegetable, and what it to my mother. I wouldn’t want to put my partner through that.
When I’m, say, ninety years old, and I’m flying home from Africa after establishing a hospital or doing something good like that, I want the plane to crash into the sea. I feel kind of bad about the other passengers, but meh.
