Ohm's Law, Voltage and Current confusion

My primary education is not the electrical/electronic field, but I do
have a science background. What I am trying to get my head around is
something I heard from a friend who said, "It is not the voltage that
kills/hurts but the amperage". I understand that statement to a
certain point, but not satifactorily enough. I get the idea of the
Coloumb -- it is the most straightforward to understand. The amount of
"charge carriers" (electrons). I find the concept of Amperage fairly
well straightforward also. A rate at which these charge carriers pass
an arbitrary point (or plane). It makes fairly well good sense that
difference of rate of these "passing/moving through" (a current) the
body will give differences of intensity of the "shock". Now, when I
think of the formula E=I/R, I imagine limits of the numerator and
denominator. You could have a very small current, but if the
resistance is nearing zero, the EMF/voltage will approach infinity or
at least be very high. So if you have, say, 3000 volts, and the
resistance is very low, so that the current is low, a very small
amperage would flow through the body when you touch the terminals of
the object of energy in question with that voltage ( a short?), so the
coloumbs (amount of charges) is low. Now 3000 volts should fry
somebody in normal circumstances. This, finally, leads me to the
question; if a battery/generator or whatever source has 3000 volts, is
their a minimum practical size it has to be and therefore a minimum
Coloumbs it must have?