The Importance of Manners

Hadith - Bukhari's Book of Manners #271, Abu Dawud, Tirmidhi, Ahmad, and Ibn Hibban.
...Abu Darda' reported that the Prophet of Allah, upon him be peace, said, "Nothing is weightier on the Scale of Deeds than one's good manners."

Hadith - Bukhari's Book of Manners #286 and Ahmad
Abu Huraira, r.a., said, "I heard Abu al Qasim (the Prophet saaws), say, 'The best among you in Islam are those with the best manners, so long as they develop a sense of understanding.' "

Hadith - At-Tabaraanee collected it, and Albani authenticated it in Silsilatul-AHaadeethis-Saheehah (#432).
The Prophet (saaws) said: "The most beloved of Allah's servants to Allah are those with the best manners."

Hadith - Sahih Bukhari, Muslim, and Tirmidhi
... 'Abd Allah ibn 'Amr said, "The Prophet of Allah, upon him be peace, was never obscene or coarse. Rather, he used to tell us that the best among us were those with the best manners."

Hadith - Sahih Bukhari, Muslim and Ahmad
... Anas said, "I served the Prophet of Allah, upon him be peace, for ten years. During that time, he never once said to me as much as 'Oof' if I did something wrong. He never asked me, if I had failed to do something, 'Why did you not do it?,' and he never said to me, if I had done something wrong, 'Why did you do it?' "