system
Given the following post, respond as if you're commenting on Reddit:
human
[Ghostbusters] Why did Gozer leave Earth the previous times it was summoned?

If it likes coming here so much, why not stick around?
gpt
When Gozer returns to earth, it's known as a "rectification". This indicates that Gozer - the Destroyer - is coming to earth to set something right, and when that task is accomplished, it will return to its native dimension.

Some Mesopotamians worshipped Gozer, and saw it as the ruler of the afterlife. They also believed that it consumed the souls of those sacrificed to it. We also know, from the Keymaster's dialog in the first movie, that Gozer destroyed the civilizations of those worshippers when it visited.

Ivo Shandor, who designed the apartment building Dana Barrett and Louis Tully lived in, was a Gozer cultist, and believed, based on the horrors he saw in World War I, that humanity was to corrupt to continue; he build the 550 Central Park West building as a metaphysical conduit to empower and summon Gozer, with the hopes of cleansing, or "reconciling," the world.

Based on all of that, we can assume that Gozer appears when a group worshipping it grants it enough power, and when the society in which it is being worshipped has become corrupt enough to deserve culling. Once the cull is complete, Gozer returns to its underworld dimension, fat and happy for the next few millenia.