There are many aspects to derech eretz (civility, proper social conduct). Our Sages said, “Derech eretz comes before the Torah.” We also learned in the Mishnah: “If the spirit of one’s fellows is pleased with him, the spirit of the Omnipresent is pleased with him” (Avos 3:10). This is an important rule with regard to derech eretz: One should do what is good and proper in the eyes of God and Man and he should put aside his own wishes in favor of the wishes of others. Let him get along with others.
As much as one learns about the laws of derech eretz it is not enough until he grasps the ideas intuitively, for there is no limit to these matters. It all depends on the time and place, and each person must be treated in according with their temperament and in accord with how they would like to be treated (as long as it does not go against the will of the Creator).
A person must always be careful to not be a burden upon his fellow. The words of King Solomon, in the Book of Proverbs, are therefore so invaluable: Let your feet be scarce in your fellow’s house (Mishlei 25:17), for it happens that one thinks he is honoring his friend by going to his house and spending several hours there. But he does not know what is in his friend’s heart, who is secretly thinking, “When will he leave already?” because the friend had other affairs to attend to and because of the visitor he is being delayed. Sometimes the visitor’s words are more of a burden then the heaviest loads, either because they are “words of a complainer” that are like “someone who wears himself out throwing firebrands” (cf. ibid 18:8 and 26:18), or because the fellow waxes on and on, or because he tries talking about things that he really does not understand.
Therefore each person should act with measure, and let his words be pleasant to those who listen to him and brief so that they do not tire of them. Public preachers must also be careful that they do not speak for too long. Being brief is better; those who need to hear will hear.