They hate each other a lot. In almost any social media you'll see them insulting and attacking each other over national/religious lines. They just don't air it in English.This is interesting i never knew najd was a geographical term. Apparently it refers to highlands. When i was looking into sharxi of the hadiith they mention other hadith where Rasuulullaah Scw points to the east and says from there will come shaydaans horn, and from there they conclude this refers to the highlands of iraq
There is a hadiith very similar to the one i showed but narrated by AlTabaraanii let me show you
وعن ابن عباس رضي الله عنهما قال دعا النبي صلى الله عليه وسلم : اللهم بارك لنا في صاعنا ومدنا ، وبارك لنا في شامنا ويمننا . فقال رجل من القوم يا نبي الله وفي عراقنا . قال : إن بها قرن الشيطان ، وتهيج الفتن ، وإن الجفاء بالمشرق . قال الهيثيمي في المجمع : رواه الطبراني في الكبير ورجاله ثقات .On the authority of Ibn Abbas (may Allah be pleased with him), he said, "The Prophet (peace and blessings be upon him) supplicated, 'O Allah, bless us in our Sa' and Mud, and bless us in our Levant and Yemen.'" A man from among the people said, "O Prophet of Allah, and in our Iraq?" He said, "It is the horn of Satan, and it stirs up sedition, and harshness is in the East." Al-Haythami said in Al-Majma': It was narrated by Al-Tabarani in Al-Kabir and its chain of narrators is trustworthy.
This hadiith does confirm najd that the man was referring to meant iraq most likely. Although i dont know why he suddenly started dissing Yemen and Shaam