If I have a hypothetical infinite 3 dimensional universe uniformly charged I can argue that the electric field is zero at any given point in space by symmetry. However, if I invoke Gauss' Law I find a non-zero flux of electric field through a gaussian surface encompassing any amount of charge. How can this be if the electric field is everywhere zero? I asked a friend about this and he noted that the problem is not well posed because it requires an infinite amount of energy to assemble such a system. I found this explanation lacking. After all, we use infinite lines and planes in the teaching of electrostatics all the time.