In your opinion, what are the primary problems of humanity?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Turning away from the Divine Guidance and straight path constitute the main problem of humanity. Human beings lead a life full of caprices, lusts and whims and ignore the wisdom behind their creation:, i.e. they worship other than Allah and forget about Allah's worship, which is the goal of life.
Allay says; {And I (Allâh) created not the jinns and humans except they should worship Me (Alone).} [51:56]
They pay no attention to the teachings of Islam in daily life. So, they become Muslims in name only, and this causes injustice and aggression among them. Life will not be orderly and sound unless people (especially Muslim) adhere to Islam.
Allah says: {…. then whoever follows My Guidance shall neither go astray, nor fall into distress and misery.[] "But whosoever turns away from My Reminder (i.e. neither believes in this Qur'ân nor acts on its orders, etc.) verily, for him is a life of hardship, and We shall raise him up blind on the Day of Resurrection."} [20:123, 124]
{It is those who believe (in the Oneness of Allâh and worship none but Him Alone) and confuse not their belief with Zulm (wrong i.e. by worshipping others besides Allâh), for them (only) there is security and they are the guided.[]} [6:82]
{"And verily, this (i.e. Allâh's Commandments mentioned in the above two Verses 151 and 152) is my Straight Path, so follow it, and follow not (other) paths, for they will separate you away from His Path. This He has ordained for you that you may become Al-Muttaqûn (the pious - see V.2:2)."} [6:153]
{Whoever works righteousness, whether male or female, while he (or she) is a true believer (of Islâmic Monotheism) verily, to him We will give a good life (in this world with respect, contentment and lawful provision), and We shall pay them certainly a reward in proportion to the best of what they used to do (i.e. Paradise in the Hereafter).} [16: 97]
Islam is the religion of sound nature and straight disposition and the true religion, which leads its followers (and others if they follow it) to happiness Here and Hereafter. It is suitable for all times, all places and all nations. It gives the best solutions to the chronic problems of humanity. It is the religion which Allah has chosen and accepted for Muslims and all His servants.
He says: {….This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islâm as your religion. ….} [5: 3]
Allah knows best.