Concentration is a skill that is difficult to obtain in our fast paced society. We are constantly having to multi-task. Pilates asks that you set your day aside and instead focus on each movement from the inside out. This is not an easy principle. It is asking for your attention for the full time you workout (up to an hour in a class situation). Even transitions. Mindful movement.
You will get more out of your workout the more you pay attention to each time you twist, turn or bend. Learn which muscles tense up when they don't need to work or recognize when you hold your breath. Details make up the whole. Anyone who knows Pilates realizes its like the game of golf; very hard to master. However, the more you may attention to how your body feels and looks during each exercise, the greater the benefits. Quality over quantity.
So next time you pop in that DVD or are in your class, remember your workout is all about you. You must be mentally and physically present to rep the rewards.