That's a crazy reason, but it's as good as any I could make up...

I've always thought there had to be a reason for everything, 

didn't you? I never could figure out why they do this, and it 

made no sense to me at all. At least not until now...

 

Women’s shirt buttons are on the left-hand side because wealthy women used to be dressed by their maids (and of course most of the maids were right-handed, right?) so it was easier for the maid to access. 

At least that's what I read, so I'll stick to that theory...