If you're doing the right thing, it doesn't matter what other people think of you - but how do you practice not caring about public opinion?
The students of the Novhardok yeshiva used to practice by going into a store and asking for a product not sold there - e.g., they would enter a pharmacy, and ask to buy a hammer.
As the joke goes, if you try this in America, the pharmacist will ask you, "What size?" but in the specialized shops of pre-war Europe (Rav Elya Pruzhiner's family shop, for example, sold only yeast and salt) it was a truly ludicrous request.
How can this story be true? I asked one day, a few years after I heard it. Isn't it problematic to give the clerk the impression that Torah students are crazy?
"It is true," answered the rav at whom I threw the question. "I knew the daughter of an old Novhardoker, and she said that when her father came to America, he would try to pay for his groceries with Monopoly money. And when the clerk would say, 'Sir, you cannot pay with this,' he would assume a confused air, and ask, 'Why not?'"
|I do not own this image|
I was enthusiastically describing the unusual individualism of P-town's alternative culture (Keep Portland Weird!) to an elderly rebbetzin of Jerusalem, and she exclaimed, "That's not good! There's no normal to keep people on their toes."
Which is the flip side of not caring about public opinion.
Dostoevsky said, 'Where there is no God, everything is permitted', but where there is no objective definition of Good and also no normal, what, save fear of the government, is to prevent the selfish from committing any crime they want?
Keep Portland Weird and Idealistic!
Evidently you have to care even in a Torah society: the Netziv once chided his nephew for not caring whether the post office staff would laugh at him for including extra information in an address, saying that a person immune to public opinion has lost a useful motivation to behave properly (and to tell the truth, and so is disqualified from testifying in court).
You have to not care about public opinion... but you also have to care. It's probably one of those things that should be swung either way and eventually allowed to settle somewhere in the middle.
Anyway, wouldn't you just love to gather up all the self-conscious teenagers of the world, hand them a wad of Monopoly money, and send them shopping? Such a powerful lesson.