Nose Tweaking, the Ultimate Insult

Tempted to tweak?
Though difficult to imagine today, there was a time when grabbing someone's nose and giving it a twist was an insult so egregious it was likely to end in one of the parties' death. For centuries in both America and Europe, violation of a man's honor demanded retribution by duel, and though by the middle of the 19th century duels were theoretically illegal in all states, they were prevalent among the elite class in the South up until the Civil War.
Evidently the nose was a particularly sensitive spot for insult, probably because in those more modest times it was the part of the man always public and exposed and tended to be associated with a man's assertion, will and confidence. Present day psychologically-inclined historians even speculate that the nose was a stand-in for—how should we put this delicately?—another item of protuberant male anatomy synonymous with masculinity. So to insult the nose was to insult the man deeply to the core.

As we see in Beaufort 1849 nose tweaking is how Johnny finally goads Jasper into a duel: 
 "No," Johnny said, shaking off his host and turning back Jasper. "You'll fight me, Wainwright, or you're a coward." There was a collective intake of air at this, followed by several gasps as Johnny accentuated his defaming words by reaching out his hand to tweak his adversary's nose. Johnny might have succeeded if Jasper hadn't grabbed him hard by the wrist, or perhaps he did succeed for the briefest of instants, it was impossible for anyone besides the two involved to know for sure. But now the course was set. The insult was too grave to be ignored by even the most lenient of standards, and the standards for gentlemen in Beaufort, South Carolina were not lenient.
A personage no less than President Andrew Jackson possibly suffered the dishonor of a nose tweak—while he was president! (Where was the Secret Service?)  Five years after Jackson had removed naval officer Lt Robert Randolph from military service, the disgraced man approached Jackson, made as if to shake his hand, and then reached out to the jutting appendage instead.  (As we know from our twenty dollar bills, Jackson had a good-sized one.) In response, Jackson tried to beat Randolph with his cane but was prevented by the other men in the room. A friend immediately offered to go kill Randolph, but Jackson refused because one's honor could only be defended by oneself. Afterwards Jackson denied that Randolph or anyone else had ever successfully tweaked his nose, thus his honor had not been compromised. Jackson was no stranger to duels--in the course of his life, he fought in thirteen and had been wounded so frequently (with the bullets often not removable) it was said that he "rattled like a bag of marbles."
I wonder which customs we feel strongly about today will cause people 150 years from now to scratch their heads and say, "You've got to be kidding!"