The slipper might be something of an elegant prop in Cinderella but in the real world it's an emblem of growing old - who doesn't remember visiting their grandparents as a child and marvelling at their soft, comfortable footwear? Slippers might be something you avoid as a young adult but once you hit 30 the stigma attached to them suddenly slips away, replaced with the prospect of toasty warm feet all year round and a decline in the problem of holes in socks...