Romans were a very superstitious people who invented deities for all the things in the world such as bathrooms, doors, curtains, suffering, depression, etc.
Deities were used to make sense of bad luck, or of bad "omens". Whenever someone did something to get the anger of the "gods" they were "punished" with bad things happening, like stubbing a toe (such pain).
Whenever the Romans had a war and barely won it, they adopted those people's "gods" as their own, the only slight change they made was that they changed their names into Roman names. One example of these is when they adopted the Greek "gods" as their own.
Temples and Festivals
The Romans built huge temples for their "gods" and "goddesses" near the forums. There were so many deities that in one year, the rich Romans, and politicians would host two hundred festivals, each one for a different "god" or "goddess".