I've never had an issue navigating around shinjuku station as once you get an understanding of the basic layout it's pretty easy. Shibuya however I just can't get the hang of, I don't know what it is but I can take the same train, same carraige, be trying to get to the same exit and sometimes it takes me 5 minutes to get out and other times it seems like it takes 15. I've just put it down to the fact that its shibuya reminding me that I'm really far too oyaji for it and I should go back to shinbashi.