I don’t know about you, but I am disturbed by those who do not respond to letters, email, or return phone calls within a reasonable time frame. In fact, in the event of a first time correspondence, it is the only gesture that allows me a feeling of that person’s level of derech eretz.
It seems that I am not the only one who views failing to respond to others in a timely manner as distasteful behavior. Rabbi Chaim Palagi writes:
"Derech eretz kodma l’torah….Therefore, one who has received a letter from a friend should respond immediately as there are a number of prohibitions which one may violate by not responding in a timely manner. Responding to a correspondence is basic derech eretz, and causing one to long for a response has the potential to cause that person long term health concerns… It may just be that the one’s reply has the ability to lead to having a mitzva performed… Not responding causes the one who sent the letter great pain waiting for his needs to be addressed. It is also cruel and a sign of arrogance. He who judges the world will pay back such people midda k’neged midda. I myself have sent letters to many prominent people, and those who did not answer my letters fell to unfortunate circumstance."