There was strong social sanction against bragging or even implied arrogance in my family. You would never say you were the smartest person in the class, or the most popular - you waited for someone else to say it about you, at which point you would demur, noting several other people who were smart or popular. Other people's ideas were not to be rejected right back at them, if offered in the proper spirit. Something good must be found in your companion's idea, and attempts at accommodation must be made. There were layers of exception to this, such as male banter allowing extreme insult as an expression of bonding and affection. Yeah, let's go drink beer up there and get chased through the woods by the cops again and you can leave me for dead while you save your sorry ass. Great idea. There is also a Yankee tradition of deflating showoffs with wry comments, which may not even sink in until you are gone. I have wondered if it is a northern European, especially Scandinavian Lutheran thing. Or whether it is a value most intense in New England. Or just good manners nationwide.
Don't toot your own horn. Bragging is unseemly. Pride goeth before a fall. Sit at the lower place and wait to be called to a higher. Display is in itself suspect. The arrogant are tempting the Fates to bring them down.
It is a good enough value, but it like all virtues, it carries its opposite vice in its bosom. People brought up with this learn to quietly congratulate themselves about how humble they are. And, congratulate each other how modest they all are, not like those braggarts from the wrong side of the tracks. They learn to hint and angle for compliments, to disguise their self-promotion, to show mild disdain - in tones that speak volumes to those in the know - for others. Wearing religious jewelry, except perhaps a teeny cross necklace, is taken as a sign that one is in fact not religious. Only the falsely religious make a show of it, dear. T-shirts with flags? Uggh. Perhaps a tie pin, or a small lapel pin if one is a veteran, but no more than that. Such displays brand you as some false patriot, a hypocrite.
It is pretty easy to see that this is a value of taste, making understatement in itself a virtue. Well, it's easy for everyone else to see this. Those enslaved to this particular god don't see it themselves, of course. They see only that those others must be hypocrites, because they have offended against good taste. This is Value Central for the Arts & Humanities Tribe.
How this starts to impact one's political, social, and religious beliefs should be abundantly clear. If anyone says that America is the world's greatest nation, they must be taken down a peg. Taking Americans down a peg is perhaps the first goal of European elites, and they would do it even more if it didn't cost them so much.
In the 60's and 70's it was thought to be very closed-minded to believe that there was nothing good to say about the USSR. One might believe that democracy and America were generally better, but it was the mark of a boor, an unthinking jingoist, to write off half the world - an entire political system as being valueless. Such extremity couldn't possibly be true, and thus those others who saw value in alternative ideas must be the open-minded ones, the thinking ones, the balanced ones.
You can see for yourself how well this false dichotomy was played in growing the ranks of liberals. If you say that the free market is much better than socialism, you must really mean that the free market is perfect, and results in no problems. Therefore you are an immodest boor who can't be correct. If you say that America is the greatest nation, it is just code for saying that Europeans and Latin Americans and Orientals have no value at all, and that all their customs, foods, and art are worthless. But liberals love foreign food and foreign art - it is their mark of how sophisticated and open-minded they are. So you must be stupid, unwilling to make the slightest effort to learn from other countries.
In its earlier stages it is merely irritating, requiring that one makes proper obeisance to the negative things about Christianity, or America, or the free market, or any other institutions of the west. Wishing to make reference to the settlement of America, some demurrer about slavery or Native Americans or the rights of women must be mentioned at every turn or one will be upbraided. Reference to the Christology of the church in the Early Middle Ages must include incantations about the Crusades, doctrinal rigidity, and the Inquisition. It is not only tiring, but effectively dictates what can and cannot be discussed. It blurs the focus of intellectual discussion, so that everything might be dragged back into the disputant's preferred narrative of oppression and exploitation. Did the Puritans and natives of Massachusetts Bay get along better for 50 years than the European tribes and local Indian tribes got along with each other? No matter. Lord Amherst approved giving smallpox blankets to the Indians a century later, proving we were just evil, don't ya know. And we didn't respect Native American religious beliefs either.
This irritation, given full rein, eventually poisons and polarizes all discussion. In the end, one can't make enough obeisance or recite enough incantations to obtain a platform. The opposite extreme, which sees only the oppression and exploitation can then rule unchallenged. Thus does the virtue of modesty devour itself, swelling into ever-greater arrogance.
When I state this so emphatically, I will easily be accused of exaggerating. Put so baldly, good liberals will insist that they of course don't mean any such thing, and that it is I engaging in the false dichotomy. I wish that were true, because the national discussion would get on better if it were. I would love to say I am just going over-the-top to make a point. But people actually write and say these things all the time. I get into discussions about historical, social, or religious issues all the time. Whenever a liberal hits the conversation, the proper bows must be made to one god or another of political correctness, at the beginning; after each positive point about the virtues of the west; and finally in benediction as well.