Arrays start at zero because what you're counting is how far you're moving a pointer from the initial address in memory, not the items themselves. Array[0] is literally 'read what's at pointer sizeof(n)+0 from the start.' Zero-based indices make perfect sense when you know what they actually indicate.

Although to be fair, starting with one and actually counting the items makes sense too, and seems more intuitive, and this may not even apply to Lua at all. But one-based indexing is still wrong regardless.