Salaam
Wherever we go we should give salaam, we should fill this world with peace , now the question i am about to answer is what if an arrogant/ignorant person says and speaks bad to you ? We are commanded to walk away and speak words of peace , in quran and sunnah it tells us to speak calmly and spread peace even if someone speaks arrogantly , the patient are rewarded , Isn't our deen the deen of peace and justice? It is best to give salaam to even muslims we dont know in my opinion. Stay on the right path and always speak peacefully and be humble !