>It's impossible to make things without parasitic capacitance because without a perfect insulator...

Maybe a nit, but I don't believe that is technically correct. Parasitic capacitance (and inductance) exist between any two objects because the electric (and magnetic) field extend from a charge (or current) to infinity. These fields store energy, even in perfect vacuum. The lumped circuit model of stored electric energy is capacitance, the model of stored magnetic energy is inductance so anything physical which carries charge or current will have capacitance or inductance (will store finite energy). An insulating material (dielectric) in a capacitor can increase the energy storage (by the sqrt of the dielectric constant of the material) but non-ideal materials are not necessary for the "parasitic" effect to occur.