Every time my wife and I picked up my son from summer Boy Scout camp, we were treated to a ceremony that included wonderful, outrageous boasts. Each troop tried to outdo the others with ridiculous bragging. The object seemed to be both a manly exercise and a test of language skills. For me it was simply fun.
I've always been attracted to tall tales, out-sized insults, and boasts. They show up a lot in Shakespeare. I watched Henry V this weekend, and they inspired this blog's subject. This from the feckless Dauphin:
“When I bestride him, I soar, I am a hawk: he trots the air; the earth
sings when he touches it; the basest horn of his hoof is more musical
than the pipe of Hermes.”
From someone else, it might come off as dignified, but he is revealed to be delusional. His soldiers don't believe a word of what he says, and the audience is encouraged to be as skeptical. So boasts, and how they are set in a story, can both reveal character and can foreshadow later action (the Dauphin's defeat at Agincourt).
In the New Testament, there's a nice turn by St. Paul:
"If I must boast, I will boast of the things that show my weakness."
A reverse boast goes in the opposite direction, often revealing fears and insecurities, but it also can reveal hidden strengths. I usually try both kinds of boasts as I explore a character.
Boasts often include powerful comparisons and metaphors: Eyes of an eagle, a mountain of a man, lion-hearted. "I am a hawk." But the best, most useful boasts are about doing things, often tangible, even visceral things like eating, spitting, having sex, and fighting. Powerful verbs combined with elemental forces -- stamping mountains into gravel -- make great boasts.
Again, it's likely most boasts you develop won't make it into your stories, but they can provide fresh perspectives on characters and help you to explore their limits.