Consuming excess nicotine is a pretty horrible experience. You just feel super ill and nauseous. But you don't have to use an ecig to do it, just buy a stronger cigarette and smoke 2 or 3 quickly. Or you can eat part of a cigarette. Or just smoke a big cigar and inhale it like a cigarette.

Anyone who smokes has experienced feeling sick from nicotine and quickly learn to avoid it because it sucks.

You build a tolerance and ecigs make it easy to climb up that ramp where regular cigarettes are harder. People get to the "10 packs a day" of smoking and to the point where there's just limits to how fast you can smoke.

Vapes make it a lot easier to blow past that amount of consumption.