It only takes 6mA, that's 0.006 Amps to stop your heart, not 0.5A (500mA) Medical grade earth leakage devices operate at 10mA or lower for this reason. Domestic ones typically operate at 30mA.

It's normal to use the analogy of the size of the pipe as being like circuit resistance because it's what restricts flow and the line pressure as being like voltage.

Personal best shock voltage, 45kV. Worst injury, lost the surface of both eyes (and the skin off the back of my right hand) to flash burn. Picture of right eye available on request. Think twice before requesting.