When it comes to clothes shopping, there are all manner of reasons that a woman will send a garment back to the rails. Wrong colour, wrong cut, wrong shape. . . right size.
A piece of clothing can tick all the boxes, but if the size on the label doesn't boost the ego -- even if it fits perfectly on the body -- it's not coming home.
I've lost count of the number of times that my delight has dissipated into horror when I've discovered that the size on the dress that I thought I would never find is, in fact, in a size that I thought I could never reach. In most cases, I've left the boutique empty-handed and en route to the nearest health shop.
Let's face it, most of us would rather take the pair of jeans that cuts off circulation and sends love handles spilling over the waistband ("I'll slim into them") rather than buying the next size up.
A friend went lingerie shopping recently. Despite being measured by the assistant, she insisted on trying on a bra in a smaller cup size.
When the assistant pulled back the curtain and discovered that the bra gave her four breasts rather than two, she point blank refused to sell it to her. My friend refused to buy the next size up and promptly marched out of the shop.
In our ignorance, we tell ourselves that not buying the garment is an exercise in self control. In truth, the only area in which the item differs in size from all the other pieces in your wardrobe is the tiny digits on the label that nobody but you is going to see.
Changing room stand-offs are on the wane, however. In recognising that the size label can be the difference between a woman buying or abandoning the garment, retailers have craftily lowered their sizes or made their garments more accommodating.
Take size zero (roughly a UK size 4 to 6). Many forget that the size wasn't developed to clothe ever diminishing bodies, rather to flatter women who are obsessed with having a tiny frame. Other US stores have introduced small and extra, extra small sizes to suit their customers.
Witness vanity sizing for yourself by trying on your 'size' in high street shops Zara and Marks & Spencer. You can be assured that the digits on the labels won't be the same.
Retailers are pandering to our size insecurities to increase their bottom line. By and large, manufacturers are making women's clothing bigger and labelling it with smaller sizes.
The question is: how far will it go? Will today's size 14s soon be slipping into size eights? Will 'size zero' become 'minus four'? What affect will vanity sizing have on the obesity epidemic when women with a few pounds to shift are delighted that they can finally fit into a size 12?
It's ludicrous that women don't buy clothes with unflattering size labels, even if they fit perfectly. It's utterly deluded that we'll buy the very same garment if the retailer doctors the size tag.
It's a grand illusion that we are all complicit in and while it gives us the feeling that our waistbands are trimming up, in the long run, vanity sizing can only lead to us filling out.