Exercise to stimulate, not to annihilate. The world wasn't formed in a day, and neither were we. Set small goals and build upon them.
Exercise should be done to stimulate your body, to build it up, to make yourself better and stronger. It shouldn't be punishment, or to break your body down. It shouldn't be because you hate your body. That is not the point. Exercise because you love your body, because you love the feeling of your body moving in space, because the thought of not being able to move is terrible.