Negative resistance is simply exampled by a low Farad capacitor discharges current faster than it gets charged up with current. Capacitors have what is called: equivalent series resistance in that a conventional ceramic capacitor has the equivalent resistance of around 10 milli Ohms.

But this is an average based on a presumption of whatever value of capacitance we set this capacitor to. It does not take into account that small pico Farad capacitors discharge their voltage potential at a rate of current faster than whatever rate of current which charged them up.

Likewise, it does not take into account that large kilo Farad capacitors discharge their voltage potential at a rate of current slower than whatever rate of current which charged them up.

And if we get a negative resistant electronic component somewhere nearby, then current will build up and maybe at a rate faster than the positive resistances inside the circuit may destroy it.

In this example, of http://is.gd/simpleparametricexcitation, I made the mistake of giving its coils a slight edge in that they possess negative resistance rather than like a conventional coil possesses positive resistance. This means that whatever current passes through these coils gets a boost rather than getting slowed down.

It would be like running around a track and every time you pass the starting point, a group of people give you a push to make sure you don't slow down.

This is negative resistance... A push, rather than an obstruction.

Positive resistance is an obstruction to flow. Negative resistance is a push, or a pull, which accelerates the flow rate of current.

So, you could say that positive resistance is a sinkhole for voltage potential since voltage potential was the original source for current to emanate from out of it. While negative resistance is a source of additional (voltage) potential which adds, rather than subtracting, from the flow of current.