What about the custom of saying good morning to someone, and they don't answer you?
Now this very bad custom of neglecting to answer is the result of lack of chinuch. People have to be trained, and I must say this, you cannot learn any Gemara unless you have Rashi; you need tosfos, you need more meforshim. The truth is however, even on Rashi and tosfos you have to have a Rebbi. That's why there are Rosh Hayeshivas who explain the sugyah. It's not enough to sit down and learn by yourself, because many times you'll be lacking in appreciation of what's really being said here.
When boys for instance learn Bava Kama in a Yeshiva, and they learn all about arba avos nezikin, four kinds of damages, and they learn, one of the mazikim is adam, man is a damager. Now it's not enough to learn that piece of Gemara. The Rebbi where ever he is, even in the biggest yeshiva must take time out to explain to his disciples what it means when people damage other people's property.
If a boy is riding a bike, and here is freshly laid paving, and he is careless, or he is a vandal, and he drives his bike onto the wet cement and he mars it forever and ever, that's a vandalism. A yeshiva boy who does such a thing wasn't taught properly.
So children have to be taught not to commit vandalism, that's called nezikin, not to be a mazik. It's not enough to learn, it has to be explained in practical ways by the teacher, by the Rebbi.
And that's why people have to be taught, when the Gemara says that a man who does not answer you when you greet him is considered a robber, that has to be taught to children, that has to be taught to adults also. You must answer if somebody greets you, and it's an evil illness, when people are so raw, so untrained that they don't understand this.
Some people do answer, but it's almost invisible, they give a nod, you need an oscilloscope, you need a special instrument to see if he nodded his head! Or he mutters something; you need something to magnify the sound. He should answer clearly and he should make a noticeable motion with his head, he should acknowledge your greeting, that's the minimum a person should do.
That training has to be taught to children by parents, children have to be taught the realities of Torah in actual life, because otherwise they are not practicing the theories that they are being taught.
You know that there are boys who learn about stealing in the Gemara, and some of them have good heads, and they can talk about tashlumei keifel, and things like that, and they know that halochos, and still they wouldn't hesitate to steal a Gemara from a beis hamedrash to take it to the yeshiva without permission.
Now what does that mean? It means theory and practice are divorced from each other; it's up to the Rebbi to translate that into actual fact. You cannot take somebody's Gemara, you need permission. You cannot take a sefer from a synagogue without permission.
You have to answer when somebody greets you, otherwise you are a robber, because it's your duty. Once he says something to you, it's your obligation to payback; if you don't you are a robber.
Good Shabbos To All
This is transcribed from questions that were posed to Harav Miller by the audience at the Thursday night lectures. To listen to the audio of this Q & A please dial: 201-676-3210