I think being stranded out in the middle of the ocean is intimidating. Whether a killer shark is after you, maybe the boat or ship is haunted. I’ve watched the game boy color game, Resident Evil Gaiden, and that game really sets the bar to me as to how scary being in the middle of nowhere in the ocean can be. With packs of zombies on board and a deadly bioweapon as well, with no way out.
Maybe more common than many think, but I know a lot of former servicemen. I struggle to think of one who has a positive perception of any of our military actions.