Today the Talmud explains the concept that when a certain place has a custom, we do not violate the custom in front of them. The customs in question are not actual law, but when a place adopts a custom they often assume their way is only way.
The Gemara brings a juicy example:
Two brothers may bathe together, and there is no concern this is immodest or will lead to sinful thoughts. However, the custom was that two brothers do not bathe together in the city of Kabul (near Tyre per I Kings 9:13). And there was an incident involving Yehuda and Hillel, sons of Rabban Gamliel, who bathed together in Kabul, and the entire city denounced them and said: In all our days we have never seen that type of outrageous conduct! Hillel slunk away and went out to the outer room and did not want to tell them: You are permitted to do so.
It is important to note that in ancient times they used public baths and it was normal for men to see other men in the bathhouse.
There is an incredible humility here. What the brothers did was absolutely allowed according to the letter of the law, but they did not argue with the locals. We also see that the men of Kabul overreacted to a violation of their local custom, as if it was the worst sin possible.
The practical wisdom for us is that when people are set in their ways, don’t bother trying to change them. Other people assume their own personal practice is the only right way. They will react strongly to any sign you disagree. Convincing them they are wrong is impossible.
The Gemara notes that this is correct when the custom was established as a stringency or protection for the law. If the custom was based on a mistake of the law, the rabbis would work to change it.
Red Pill Rabbi 