The Prophet of Islam said: الْمُسْلِمُ مَنْ سَلِمَ النَّاسُ مِنْ لِسَانِهِ وَيَدِهِ (Musnad Ahmad 7086) A true believer is one by whose hands and tongue people are safe. This is the Islamic principle: Live in society in such way that no one experiences harm due to your actions or words. This will create harmony in society. A hadith says: وَاللَّهِ لَا يُؤْمِنُ، وَاللَّهِ لَا يُؤْمِنُ، وَاللَّهِ لَا يُؤْمِنُ الَّذِي لَا يَأْمَنُ جَارُهُ بَوَائِقَهُ (Sahih al-Bukhari 6016) By God, he is not a believer whose neighbour is not safe from his evil. 
What does this mean? One who creates problems for his neighbours is not a true Muslim. One who creates problems automatically excludes himself from Islam. This is indeed a great teaching. If you live in a family, society or country, wherever you be, it is God's obligation upon you to not create problems for others. You must live as a no-problem person. If in a society, people consider this principle as part of their religion, then that society will be marked by social harmony, and nothing else.  There will be peace and harmony everywhere.