"Believe it or not, every time we do a game we design a multiplayer mode just to see what we would do," Fallout 4 director Todd Howard told Mashable at E3 2015.

Howard and his team sit down and figure out what multiplayer might look like for the game they're working on. Pre-production is the best time to do that. Before anyone starts to do serious coding or content creation, concepts and mechanics are written down on paper and discussed. Multiplayer is always in the conversation at Bethesda.

"Then we go, 'Yup, we shouldn't do that. That's an awesome idea that is way too distracting from the main thing we want to do, which is single player,'" Howard said matter-of-factly. "I could see ways it would work, but development-wise, they're very different experiences."