Hand washing. I’ll come back to it.
I have this theory. Or maybe it’s just an idea. It’s about the advantages you give your characters. And how many advantages you can give them without distracting from the story or making them unbearable.
Advantages? Beauty is one, and very common; but there’s also intelligence, skill, charm, grace, wit, fortune, discernment, athletic ability, good birth, kind parents, a person who encourages them to follow their dreams, etc. All of these things are wonderful. But most people don’t get to have them all. And if you write a character who does get them all, it’s sort of cheating.
This is particularly important in writing historical fiction, or fantasy set in an historically inspired context (it works for SF too, but to keep things simple I’m limiting my scope). It is easy, and tempting, to create a character who is ahead of her/his time: “You fools, feudalism is doomed! Let us storm the castle and demand the birth of democracy!” A reader may want to sympathize with a character who partakes of our sensibilities more than he does of those of his time, but some writers leave out any clue as to where that vision came from. Did the character emerge from the womb with her/his political aspirations fully formed? This stuff has to come from somewhere (Mary Todd Lincoln, who would probably have run for office if she hadn’t been a well-raised Southern belle in the 1850s, and stood behind her husband all the way to the White House and the Civil War, learned to value politics–and competition–by vying for her father’s attention with her 13 siblings).
Once you’ve opened the door to a character having a different attitude from the people around her/him the temptation is to give the character skills or gifts they couldn’t possibly have–or couldn’t have for the reasons we have them. Example: in Sold for Endless Rue I have two characters–an herbalist-healer and her apprentice–who are known for their skill, particularly in midwifery. And I wanted them to have a better than average track-record with live births and deliveries, so I had them wash their hands. Simple, right? Since Ignaz Semmelweis started talking up asepsis and hand-washing in the 1840s, incidence of maternal death from childbed fever has plummeted. Only my story takes place in 1205 or so, when germ theory was not dreamt of. So why would these women wash their hands each time they change tasks, before they touch a patient and after? The older woman, the teacher, was taught by her teacher that one should never bring the dust of one task to another lest they mingle. It’s a superstition that just happens to work out in the favor of their patients. And a modern reader can read that and think, aha! Asepsis! without Crescia and Laura having to have a conversation about washing away these tiny invisible carriers of disease…
So that’s my rule of one. You can give your character one advantage that no one else in the story has–if you can make a convincing case for it. But don’t try to give her/him two or three unless you want them climbing to the top of the barricades, waving a flag and singing the Marseilleise.