Betty and Barb are identical cousins - you know, kind of like Patty and Cathy on The Patty Duke Show? They don't dress alike very often these days - they used to do that more when they were kids. But every now and then, they get a kick out of it:
Because they both just happen to have the same sheath dress:
And, after all, like Cyndi Lauper said/sang sometimes "Girls Just Want To Have Fun!", you know?
Can you blame them?