Why isn't the universe uniform and symmetrical in all directions?

I envision The Big Bang as a circular sphere, exploding with beams of energy going out perpendicular to the face of the ball, much like the rays of a stereotypical sun (☼), though they are of course very dense and not only energy (I think). I don't get why things would start clustering though. Wouldn't all the angles between my envisioned "beams" be equal, and their gravity to one another be equal, thus rendering the universe symmetrical and "cancelling" itself?