Fumblin', your "jumper cable grounding" system is a poor indication of the overall grounding condition. Typically, jumper cables just do not have enough surface area contact, hence limiting the number of electrons in direct confirmation of the second corollary.
By the way, Article One of the Bylaws of the Serious and Solemn Convocation of Stovebolters Anonymous reads, "Do not be afraid!"
In the grand tradition of stovebolters everywhere you should persevere fearlessly. Remind yourself frequently that you are smarter, craftier, and more intelligent than any truck part, electrical charge, or fastener you may encounter. Though each will try constantly to get the upper hand, you will win.
Oh, look! We have a visitor! Joe Nelson, you know you are always welcome to join with the Big Bolt folks for a beer and a cigar. And if John ain't around, you won't have to worry about doin' any pushups!
