Why did the Sumerians think that ziggurats and sacrifices would keep the gods happy?

The Sumerians believed that ziggurats, as towering temples, served as a bridge between the heavens and the earth, allowing them to connect with their gods. They thought that elaborate sacrifices, including offerings of food, animals, and sometimes even humans, were necessary to appease the gods and ensure their favor. This belief stemmed from the idea that the gods controlled natural forces and fate, and maintaining their happiness was essential for prosperity and protection. Thus, ziggurats and sacrifices were integral to their religious practices and societal stability.