Women really are all the same from a man's point of view in one important way:
Imagine I line up five metal boxes in front of you. They are each different sizes, colors, and slightly different shapes. They each have a few buttons, knobs or dials, but no other features. I ask you which one would do the best job of measuring impedance in a circuit. If you get that right, I ask which one must never be allowed to come into contact with engine coolant.
You're guessing, right? The boxes are clearly not the same, but they might as well be, because you have no idea what any of them do.
Women are mysterious boxes. The commonality they all share is that none of them are predictable and none of them really make sense to me.