Side effect of dielectric polarization
I think you are mixing concepts such as polarised Capacitor with dielectric. 
1) I would recomend you to read WIKI: Dielectric

But basicly dielectric polarization is the distribution of charges in a dielectric material (aislator). Not all aislator materials are dielectric materials. Usually these material are used to reduce the Electric field, like in capacitors.

2) The capacitance on another hand in a capacitor filled with dielectric is explained here: Capacitance

3, 4) A good examples are wires with high tension. If you try to touch it without special protection it can kill you. Also normal wires also have capacitance and it can be different in different conditions. For example in an HDMI cable the signal may lose it's matching and this will make impossible to see correctly the image.