Flat, square, Philips and a dozen more, what are all those screw heads for? I understand why there would be different sizes; sometimes you want small screws and sometimes you want more solid screws, sometimes you don’t need to apply much torque to make sure they’re tight and sometimes you do.
But why not just one type of screw head? I would have exptected standardisation to have done its wonders by now. What gives? Is the flat head optimal for some applications while the square is best for others? Is the hardware store mafia behind it all?