For a second, you scared me, lol.
I assume I would not be pissed off, but I would keep wondering why... probably for the rest of my life. You can't do that to people. I think saying goodbye would just be the proper thing to do.
I didn't know about the goodbye post until just now. I think that if I would decide to leave for the same reasons, I would want to go out with a bang and write a very critical post about those reasons... but to each his own, I guess.
(And I'm puzzled about the underlying reason to use bidbots on that post, btw)
I'm too attached to a lot of people here to leave like that. I can't even imagine what it would be like to leave everyone behind, just like that...
(I do think most people who leave don't plan to do so. They just fade away, slowly - because life has its ways.)