ideally the hot wire is switched, and the outside of the edison socket connects to the neutral wire, so especially if the light is switched off, you're often only in a position to get a shock from whatever is on the neutral wire, which might have been what happened in the bathroom-fixture case

commonly the neutral wire has something like 20vac rms on it for a variety of reasons

if you are ungrounded (due to rubber boots or whatever) your body is in series with your capacitance to ground, and that will commonly give you just a mild vibrating feeling or nothing at all

this 'path of least resistance' thing can be pretty misleading, because if you have two resistors in parallel, the least resistance is always the parallel resistance (i.e. current through both resistors in inverse proportion to their resistances) and not just one resistor or the other