The perfect collision of programming and mathematics! The first user boldly declares "ALL ARRAYS START AT 0!" - a hill that programmers will die on. Then the math bot swoops in with the ultimate comeback by reminding everyone that 0! = 1, which is a mathematical definition that confuses even seasoned students.
It's the eternal programmer vs mathematician battle in one perfect exchange. While arrays indeed start at index 0 in most programming languages, factorial zero equals one because it's an empty product (and not because some computer scientist decided to mess with our heads).