Yazid was the son of Muawiya ibn Abu Sufyan, from the family of Umayyah, one of Quraish's families. Abu Sufyan was acting as the chief adversary in the non-Muslim's campaign against Islam. Muawiya's mother, Hind, ate the liver of Hamza, the Uncle of the Prophet, because of her burning hatred and beastliness. Muawiya too was an active opponent to Islam.
Indeed, Abu Sufyan's family was active in strategic, financial and morale boosting within in the non-Muslim's campaign against the Muslims. Their efforts, wealth and diplomacy were of great burden in preventing the spread of Islam among Arab tribes.
During the liberation of Mecca, it was suddenly besieged with enormous forces of Muslims. The unbelievers at Mecca were struck with seeing the Muslim fighters who had caught them unprepared. Thus, they the non-Muslims had no choice but to abandon their arrogance which had prevented them from accepting Gods sovereignty.
During this incident, historians recorded some peculiar stories about Abu Sufyan's family. However, there is one thing for certain that they accepted Islam unwillingly, and they were treated in a special way for that.
For instance, they were given extra donations in order to gain their hearts towards Islam. But whether this generosity had any influence to produce a change in their materialistic thinking is a different matter. Indeed subsequent events revealed no change in their way of thinking and life.
Yazid was brought up in a family whose atmosphere was electrified with the emotions of their dead family members who fought against Islam, in addition to seeing those Muslims who killed them receiving full honour and respect by society. Not to mention the wasted wealth, injured pride and stripped privileges of their family.
However, Yazid had some unique qualities in the adverse sense; he was known as a playboy during his youth. Historians recorded him being drunk, committing adultery and in general leading a very corrupt life. Some even quoted Yazid saying, "The family of Hashim staged a play to get a Kingdom. In reality there was neither news from God nor a revelation".
Even if we discarded this extreme, there is no escape from facing the rest of his shameful
deeds and horrifying crimes. Not to mention his illegal claim to rule the Muslim World, or misusing Muslims money, or intrusion upon peoples dignity and lives.