The gods actively intervene in the lives of the mortals, often using the characters like chess pieces to carry out their own power struggles. Juno hates the Trojans and does her best to stop Aeneas from fulfilling his destiny, even setting up the war that fills the second half of the poem. Venus tries to protect and help her son. Neptune just gets annoyed that some other god thinks he can mess with the ocean. Yet it's a matter of continued controversy whether the gods are meant to be fully-fledged characters, like superpowered humans with their own motivations, or whether they have a more symbolic role and act as a way for Virgil to enter into the humans' emotions and decisions. In many cases, it's difficult to tease apart where godly influence ends and human free will begins. Maybe Dido was too heedless in her passion—or maybe it was Venus's enchantment that made Dido too reckless in love. Maybe Turnus never would have wanted a war at all, without Juno's involvement. Or maybe there's no need to decide what comes from the god and what comes from the human, because even those acts of the gods are really just a way of poetically examining the irrationality of the human spirit.
In any case, within the world of the poem, the characters do believe in the gods. Faced with the constant, and sometimes invisible, intervention from the gods, all that mortals can do is pray for divine signs to guide them, try to get on the gods' good sides in times of difficulty, and appeal to seers and oracles to get a better view of the gods' desires.