I agree. I think that you shouldn't even have the mentality of "trying to get into third and manageables" because you shouldn't even want to see a first down. Your mentality on offense should be trying to get a first down or more on every play.
And having that mentality will keep you from being a great team. Sure, I'd love to score a TD every play, or get a first down every play. Really, if every play is executed to perfection, that is the result that you will get. The only offensive plays not designed to score a TD are the spike, knee, and occasionally the dive/QB sneak if its not on the goal line. Under your mindset, we should always throw a long pass on 2nd and long, which is outrageous IMO. Sure, if your WR can get open deep consistently, call the plays that go that long, but the simple fact is against most defenses you CAN'T try to get a 1st down or more every play, playcalling-wise. I think you are forgetting the fact that there is another group on the other side of the ball.