Actually, I'm relieved.
I caught and ate an octopus once, but *only* once. It seemed to take forever to die, even after I'd gutted and sliced it up [had stopped wriggling before I roasted it over a fire though]. Hopefully, what I was seeing was just postmortem neuromuscular noise, not actual suffering. I was always pretty good about being quick and painless, respectful, even toward clams, which have no brains to speak of.
Still, not an experience I'd care to repeat.