There's a great series on practical polytheism here: https://acoup.blog/2019/10/25/collections-practical-polytheism-part-i-knowledge/

tl;dr the gods cause problems if you don't appease them, and sometimes even if you do. It's basically a reminder that before you do anything you should consider relevant factors that are outside your control: the weather, for instance.

EDIT: A more direct answer to your question is that the virtue being promoted by these religions is humility, or lack of hubris (a greek concept). They want you to never forget that forces outside your control and comprehension (personified by the gods) govern every aspect of your life.