Our universe is a product of imperfection. An analogy made by Stephen Hawking discusses a large room with a perfectly level floor, with small metal balls evenly spaced throughout. In such a situation, the balls would remain in the exact same positions over an indefinite amount of time because there is an equal amount of force acting on each and every ball. However, if just one ball is removed from the floor, the forces become imbalanced. Thus, over a long period of time, movement would begin to occur due to the imbalanced forces of gravity acting on each ball. When the universe as we know it began, a similar situation occurred. The vast majority of molecules were evenly spaced, save for a few or even one that remained out of line. Just like with the small metal balls, this caused an imbalance of force, molecules began moving and therefore collected in small bunches, formed compounds and so on. A brilliant analogy by a brilliant man, may your body return to stardust.