Ben;
Let me help ease some of your fears.
FIRST fear and safety can be good when it comes to DC.
The thing your dad probably had you touch, depending on the year, was the condenser up around the coil.
Back in the "DAY" engines were spark controlled by point, rotor and condenser.
Points were the make/break circuit which happened from the mechanical action of the rotor. The condenser was the holder of that AC.
Actually, the condenser was to prevent destruction of the points by arcing on break:
- With the points closed the current in the primary rises until limited by the resistance of the wire (and the balast resistor, if there is one). The core of the coil becomes magnetized, storing energy.
- When the points open what you WANT is for the current in the primary to stop, the magnetic field to collapse, the collapsing field induce a very high voltage in the secondary, and this voltage to strike an arc across the spark plug and dump the energy from the field into the spark, igniting the fuel-air mixture.
- But without the condenser (or if it fails) the current strikes an arc across the opening points. Energy from the collapsing mag field pumps up the voltage across the points to keep the arc running, vaporizing metal off the points and moving it from the more positive to the more negative contact. Eventually the arc extinguishes and any remaining energy MAY strike a spark across the plug. But the spark is puny and its timing varies from shot to shot. Meanwhile the arc is rapidly eating the points. (You replace points and condenser as a unit, in case the points failed because the condenser was failing.)
- The condenser is a capacitor (with some series resistance). When the points open the current quickly diverts into it, charging it up, rather than striking an arc across the points. By the time it's significantly charged the points are open enough that the arc doesn't restart across them. So after a very deterministic time the voltage spike occurs and the only place for the energy to go is into the plug.
- Of course when you then CLOSE the points the charged condenser discharges rapidly through them. This would weld them if not for the series resistance of the condenser, which limits this inrush current. It does move a bit of metal from point to point, though.
- If the values of the various components are correctly matched, the amount of metal moved one way when the points close is about the same, on the average, as the amount of metal moved the other way when they open (and there's a tiny arc before the current diverts to the condenser). So the points average out to staying unburned and uneroded for a long time.
Note that the voltage spike occurs both across the primary and the secondary (though it's far greater across the secondary, which is high voltage low current due to having many more turns). If you put your fingers across the point circuit the current will try to run through you, and you'll get a "poke" there. So you can be jolted by the inductive kick either at the primary or the secondary terminals.
Danger comes when you become part of the circuit, and a normal person's skin has a high enough resistance that the electricity THAT ALWAYS takes the path of least resistance. Person's skin resistance is up in the Mega-Ohm range so just touching a battery won't do much at all.
Sweat salty laden skin is a different story 
that skin is in the Kilo-Ohm range which is also in the normal resistor ranges.
Story I heard in E.E. school: Some freshmen got into a bet on whether you could electrocute somebody with a 1.5V battery. Guy betting "can" knew that it was current that mattered and 20 mA up the left arm would do it. Guy betting "can't" got into put-up-or-pay-up mode and was convinced to sit in a chair with each arm up to the elbow in a barrel of salt water while a 1.5V battery was hooked between them.
Oops!
Went into V-fib and they were unable to get him restarted.
Fortunately this is a very extreme case of wrecking skin resistance. So you're usually safe with minimal precautions up to about 50V - and usually in for at least painful trouble at 120/240. The main hazard with up-to-48V systems is accidentally shorting a battery with a tool and pulling thousands of amps - with vaporizing metal and maybe exploding acid-filled batteries following moments later.
But if you get cut on a wire or grounded sheet metal you've got direct conductor-to-body-fluid contact. Do that twice at two voltages simultaneously and you're a potential victim of "microelectrocution" - as people once were in hospitals before the medicos figured out that it only takes a TINY bit of juice on EEG/EKG electrodes or needles to fry the patient. So use some care around even "usually safe" voltages.
When working with DC I would NOT be using a grounding strap that is normally used for static electricity dissipation. These voltages are very high voltages and the straps are used to keep those away from chips and stuff.
ABSOLUTELY! The thing you DON'T want is to give the current a better path through your body. When working on electricity one of the rules is use only one hand - preferably the right (which puts less of the current through the heart) - and avoid grounding yourself elsewhere as much as possible. Also you try to ALWAYS keep a posture and weight distribution such that, if a shock fouls your muscle control, you fall or jerk AWAY from the wiring, rather than into it or latching onto it. Better to fall off the ladder than hang up on a live wire. (And always treat things as live, as you always treat a gun as loaded. You never know when you'll get a visit from the Ammo Fairy or Reddy KillerWatt.)
