Too often I've heard about the "big uglies" who protect the quarterback and running backs. These "big uglies" are of course the offensive linemen, and they are occasionally made to look as though they are just big, fat, unintelligent guys who just get in the way of the more athletic defensive tackles and ends. As a former "big ugly," let me assure you that the offense wouldn't move without the intelligent guys on the offensive line. In fact, I would go so far as to say that offensive linemen are generally the most intelligent guys on the football field every Sunday.
Unlike other positions, we know more than just our responsibility. For example, a running back is only responsible for hitting the hole that the linemen provide and running to daylight. Meanwhile, the lineman has to set up to stop the opposing rush, has to know the snap count, has to make sure that all blitzers are accounted for, has to know where the running back is going to hit the hole and what the running back's tendency is and finally has to know how aggressive to be, depending on the play call.
And there's more to think of when you're pass blocking! I don't know about you, but that doesn't sound like the work of a simpleton.