In large part Eleven Warriors is a place full of people who know quite a bit about the sport of football. I'm often wowed by the intricate and passionate discussions of tactics and schemes that I see in forum posts and responses to articles, and often I come away feeling like I barely understand the game at all. 

But the area where I feel least informed is in offensive line play (blocking schemes mostly) and route running. I'll readily admit that I barely know the difference between an offensive tackle and an offensive guard, and that discussion of "X receiver" and "Z receiver" and so on leave me confused. 

So what are some aspects of the sport where you find yourselves underinformed or confused?