Using zero reminds you that black is 0, 0, 0 in 24bit integer rgb, while white is 255, 255, 255, not 256, since you only have 8 bits and 2^8 - 1 = 255, not 256, and calling black 1, 1, 1 makes no intuitive sense. Using zero indexes saves a tremendous numbers of errors by habituating on what is more natural for digital memory and the representation capability of intrinsics while creating a nice correspondence between hex zero, decimal zero, binary zero.

The only time this leads to bugs in Python is when using my_list[len(my_list)] instead of my_list[len(my_list) - 1], where the difference between the magnitude of indexing vs counting can lead to intuitive error. However, it's easier to just write list[-1], knowing that zero is the first element, so counting backwards has to start at a different value. Of course you can do something silly like my_list[-len(my_list)] to just be silly.

Indexing is about having some value to get some position out of an array. Zero is a unique number, so it makes sense to use it as an index. If you start counting with your fingers by holding up none and call it zero, suddenly life makes intuitive sense. If you count the numbers that you count on the way to ten fingers, you get eleven unique numbers for those ten fingers. The difference between array length and array indexing. Magic.