These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Aztec Mythology
Alternate Character Interpretation: the groups of Mesoamerica in general worshipped more or less the same gods but giving them their own spin. For instance, the Chichimec worshipped Tlazolteotl (to the Aztecs a very complex sexual goddess related to sin and forgiveness) as Itzpapálotl, a female warrior goddess. This also explains why there are several sun gods (Tonatiuh and Huitzilopochtli, as even Tezcatlipoca sometimes), several moon gods (Nanahuatzin and Coyolhauxqui) and an unspecified number of deities for the Morning Star (Tlahuizcanpantecuhtli —now that's a mouthful, Xolotl and Quetzalcoatl). Some belive that the most complex figures, like Tezcatlipoca and Xipe Totec come from Toltec culture, whereas other gods such as Huitzilopochtli are the tribal gods from the Aztec's past in Aztlan.
Values Dissonance: Oh hells yes. None of the gods are really "good" or "evil," and while people from most other cultures are horrified at the vast number of bloody sacrifices the religion entailed, they were seen as absolutely necessary to the practitioners. For instance, the reason for the child sacrifices to Tlaloc? To make sure there'd be rain. Ripping out hearts? Make sure the sun keeps moving across the sky. People being flayed alive? Otherwise the corn won't grow and everyone will starve.
Why is it so horrific when looked through modern eyes? The babies (YES, BABIES) sacrificed to Tlaloc to insure rain, had to asfixiate but not drown, and they had to be crying when put in the water, so they blocked their nose and mouth with liquid rubber and slapped around, then thrown into a pool. The hearts were indeed extracted with the sacrificial "victim" (it was considered an honor to feed the gods) still alive and through what was basically an open heart surgery performed with obsidian blades. The only one that is believed to not be celebrated as such is the crops god sacrifice; to wit: the offering was either a young virgin boy or girl, who had to be volunteered, who was offered a couple of days of unrestricted abandon regarding food and sex; meaning either had to have sex with as many partners as possible wether they wanted or not. They were then killed and decapitated (or killed by decapitation, but only because it was easier to do the following) and then their entire skin was removed to manufacture a "costume" wich was then worn by a priest who proceeded to dance around for days until the skin dried and rot; symbolizing how the seeds are planted, grow, give fruit and then dry throughout the season. Xipe Totec was HARDCORE.