Religion in The Metamorphoses is not a very complicated affair. Basically, in the worldview Ovid depicts, the relationship between mortals and the gods goes as follows: the mortals respect the gods, give them offerings and prayers, and so on. In return, the gods (a) don't utterly destroy mortals, and (b) might actually help them out. If the mortals disrespect the gods, they're in for a world of pain – just look at what happened to Arachne and Marsyas, who challenged gods to weaving and musical contests, or to Hippomenes, who forgot to thank Venus for winning him his wife. Note that at the beginning we said "the worldview Ovid depicts"; this does not mean that these practices were necessarily his own. There's always the possibility that Ovid's own views might have been closer to the philosophical and scientific perspective of Pythagoras, as articulated in Book 15. What do you think?
In the world Ovid portrays, humans worship the gods more out of fear than love.
Ovid portrays the gods as unjust.