I totally agree with the discipline thing... especially what you said about the straight lines. That is something that I really drum into my students.

As you said, to the flyer, what looks like a straight line is actually a big arch (like when flying a U-Control... To the Pilot, it LOOKS like it's going straight). I really beat it into them that they must get used to the plane flying a straight line with the ground on all 4 sides of "The Pattern"