Why was human sacrifice so common in mesoamerican societies? I know it was practiced in some form around the world, but not to the same extent as by the Mayans, Incas, Moche etc.
What is it that made all these cultures sacrifice so many humans? Did they develop the habit individually? Or is it even possible that they believed in some form in the same gods?
There's always room for discussion, but perhaps the section Those bloody Aztecs in our FAQ will answer your inquiry. The Podcast may be particularly helpful since it deals with Mesoamerica as a whole.
I should point out that the Inca and Moche are not part of Mesoamerica since they are South American cultures. The boundaries of Mesoamerica falls within most of modern-day Mexico, all of Guatemala, all of Belize, and the western half of Honduras.