Lord Siva gave Vinayaka the boon that he would have to be worshipped by everyone before they began a task. If they did not do so, their attempt would end in failure.
When the Lord makes rules, they are for everyone. He Himself is no exception to a rule. This is seen in the case of the boon He gave to Vinayaka, said K. Sambandan in a discourse.
When Lord Siva set out to destroy the cities of the three demons, His departure was a grand one. The Earth served as His chariot. The Sun and the Moon were the wheels of this chariot. The mountain Meru was His bow. The bhuta ganas were His soldiers. But Lord Siva forgot one thing. He forgot the boon he had given to Vinayaka, and He did not offer His salutations to Vinayaka before leaving. As a result, the axle of His chariot broke!
Although He was the lawmaker, He had to face the consequences of breaking a rule.
In his Tiruvachagam, Manickavachagar says that the axle of the chariot broke, but he does not elaborate further.
But Saint Arunagirinathar says what caused the axle to break was the fact that Lord Siva had not begun His journey by first asking for Vinayaka’s good will. It was Siva Himself who had conferred the boon on Vinayaka. Yet, when Siva broke the rules He had made, He had to pay for it.
When Daksha made preparations for his yaga, he invited everyone to his yaga. But he left out Lord Siva. As a result, his yaga was completely destroyed.
The invitees to the yaga had come despite Siva not being invited. So they too were attacked for, they had been silent when Daksha had violated the rule of making offerings to Siva.