"Water which is too pure has no fish"
~ Hung Tzu-Ch'eng (Chinese philosopher, 1593-1665)
So what does pure water and no fish have to do with sexy adult costumes? Well, let's re-word that ancient Chinese wisdom:
"Women who are too pure have no fun".
Ah, now it makes sense -- you can go through your whole life prim & proper and then, somewhere along the line, you see that it would have been OK to be a little more daring now & then. You really don't fall apart if you push the boundaries and step outside yourself once in a while, to be someone you think might be a bit more edgy & interesting, even if it's not really the "you" that everyone knows. That's the beauty of a costume -- it IS you, and it's NOT you!
Which brings us to Halloween, that mysterious once-a-year celebration where it's actually allowable to be your alter-ego ... the wild & crazy person you may have safely locked away deep in the recesses of your personality, but who needs to get out at least occasionally (or you just may explode from internal tension!).
By now everyone knows that the holiday we call "Halloween" has its roots many centuries ago when our distant ancestors felt the need to accomodate the spirit world by feeding them "treats", and tried to fool the bad spirits by dressing up in animal skins and other "costumes", so they would not be recognized by these daemons. From there it eventually evolved into looking like the spirit itself -- thus the ghosts & goblins -- and then to the modern version of "All Hallows Eve", where pretty much anything goes.
For a lot of adult women, "anything goes" means dressing up in a sexy & seductive outfit, to give themselves a fabulously extreme feminine experience, even if it's only for an occasional night. These same women may be forced to wear sensible heels and gray suits as they go about doing their daily professional responsibilities, or maybe they wear a pullover and sweat pants as they go through their college classes, but once in a while it just feels really good to be someone different, and we say..... DO IT!