Contradictions in conductivity
It is all about conductivity (resistance) as you mention. An electric circuit needs a complete path from the source, and then back to the source. Danger exists whenit is the human body that completes the circuit, either through direct contact or capacitance return. The human body reacts differently to voltage applied and to current through the body. Also, increasing the path length (higher resistance) or reducing the capacitance in the circuit results in less current (ohms law).


Your linoleum floor and plastic soled shoes make a very high resistance, resulting in low current and capacitance is likely minimal.  I would nominate you for the Darwin award since I know what it is like to touch the ignition wires on automobile spark plugs.  
A hair dryer falling into the bath lets the electricity go through water (Low resistance) directly to the human skin (short path length), resulting in higher current. High voltage grids use corrugated insulators to increase the length of the path of resistance.  The electricity has to follow the path of the corrugations rather than in a straight line, thus increasing the resistance. The resistance of Air is quite high.  
Same as answer 2. 

The resistance of Air is quite high.