Why don't ceramic capacitors have positive and negative terminals?

Normal Case:

Normally one will not find a polarity associated with a capacitor. Indeed, the quality of the manufacture would be put into question is the capacitor functions differently with different sign for the applied voltage.

Abnormal Case:

While common resistors are expected to function independent of polarity, it is possible to create resistors which are nonlinear and nonsymmetric in response to applied voltage. Just as diodes are nonsymmetric, one can imagine a diode-like material incorporated into the material of the capacity. There is no clear application for a nonsymmetric capacitor.

The only reason to label a capacitor as preferring one side positive over the other might be the effect of the rate of discharge is one of the charged surfaces is exposed to an environment which preferentially picks up or loses charge and there by affects performance.