Well one push factor would be they wanted to escape religious and political prosecution. Another is the Potato Famine. This was when their potatoes were contaminated and many died from starvation and disease.
I hope this helps somehow ;)
King Geroge the Third's Intolerable Acts Laws were unfair because it was a way to punish the colonists by enlisting taxes on imports and exports. Other unfair laws include the Boston Port Act and the Quartering Act which required citizens to house British soldiers and provide them food and water without any say in the matter.
The city that was conquered by the Medes and was the center of civilization in Mesopotamia is Babylon