Meditation is not following any system; it is not constant repetition and imitation. Meditation is not concentration.
I don't think more concentration is required for Robert De Niro to do what he does as for Jim Carrey to do what he does.
Michael Caine is a movie star, but he's also a great actor. I can't say that about every movie star. It's the concentration he has.
The concentration of the ferment iron in living substance is very small, being in the region of 1 g to 10 million g of cellular substance.
Acting, really, is a lot of mental fatigue, emotional fatigue, concentration... it's mentally draining.
The dangers of a concentration of all power in the general government of a confederacy so vast as ours are too obvious to be disregarded.