The decision to split the German forces away from Moscow was taken by a Hitler who had just been given his first intravenous opioid, and that is probably why Moscow never fell.

German writer and journalist

So Hitler receives this Dolantin injection, and he gets up, he goes into the meeting room, he dominates the meeting room, he feels great. He decides, you know, in front of everybody, no one is able to… no one overpowers him in that meeting. He was very good in the room. And the troops are split up. Like Leningrad is now a target. This weakens the general thrust towards Moscow. This is probably why they didn't take Moscow.