Scott Adams of Dilbert fame has this wise counsel:

Allow me to give you some advice: If you ever decide to join a cult, the first thing you should ask about is the quality of their doomsday cave. A poorly constructed cave could kill you, and that would take most of the fun out of doomsday.

…

I wonder if the other doomsday cults were sitting in their own caves, listening to the news on their radios and thinking “Those idiots! They totally got the wrong date!” I imagine the various doomsday cults are highly competitive, always trying to recruit the nuts away from the other cults. “Our cave has a flat screen TV, and every Friday is casual.”