Do not envy one another
لَا تَبَاغَضُوا، وَلَا تَحَاسَدُوا، وَلَا تَدَابَرُوا، وَكُونُوا عِبَادَ اللَّهِ إِخْوَانًا، وَلَا يَحِلُّ لِمُسْلِمٍ أَنْ يَهْجُرَ أَخَاهُ فَوْقَ ثَلَاثَةِ أَيَّامٍ
La tabaghadu, wa la tahasadu, wa la tadabaru, wa kunu 'ibada-llahi ikhwana, wa la yahillu li-muslimin an yahjura akhahu fawqa thalathati ayyam.
"Do not hate one another, do not envy one another, and do not turn away from one another. O servants of Allah, be brothers. It is not permissible for a Muslim to keep away from his brother for more than three days."
Narrated by Anas ibn Malik. Sahih al-Bukhari 6065, Sahih Muslim 2558
A short reflection
Hatred, envy and the cold shoulder are named together, and the cure is one word: brothers. Three days is the limit, so if someone is waiting for your salam, today is a good day to give it.