These past several decades there have been many different causes/reasons for a Zombie Outbreak (Biological, Chemical, Radiation, Plague, Parasite, Virus...etc).

But which Zombie-origin do you prefer...or is more believable to you?

I prefer the Romeroism of no explanation given.

Not sure if King's story has been adapted, but Cellphones have already turned the masses into zombies. They just haven't started physically attacking people..... yet.

They just haven't started physically attacking people..... yet.

Ever hear of Texting-While-Driving?

I can see how a biological or chemical agent (or radiation, etc., whatever) might cause living people to become zombie-like, and, for the sake of fiction, will even accept quasi-scientific explanations for the reanimation of the very recently deceased. But my favorite zombies are rotting shamblers like cake-hungry Uncle Nathan from Creepshow (1982) or the "Tar Man" from The Return of the Living Dead (1985), and only the supernatural could possibly account for such a thing. Of course, plausibility is hardly a major concern where zombies are concerned, but given the choice, I prefer no explanation - or the implication of "unknown forces" - to bogus science.

Maximum Overdrive had the best explanation of zombie origins.

Easily where they are simply brought back by a great evil or with no explanation. It's more disturbing to me than "oh yeah we probably should have been more careful with those fucking chemicals near this graveyard."

Anything but voodoo. Though to be honest I don't think origins of the outbreak is really necessary. It's worked in many films without an explanation

Without-Origin or No-Known-Cause or No-Reason-Given-Whatsoever seems to be the most creepy Zombie outbreak.