The seasonal “Why don’t you?” installments, the spring 2009 edition, à la Diana Vreeland. The idea for this column is explained in the very first of these series. Do keep in mind that these are all for the sole purposes of enjoyment, imagination, and fun! Whip out that credit card, and buy yourself a Valentino gown, without a thought of buyer’s remorse. Put it on a mannequin, display it oh-so-beautifully as if it was in its boutique window in your room. Admire it, love it, an wear it at some gala or an evening party! Throw those flannel pajamas and oversized tees away and parade about your home in thigh high socks, a little teddy, and a lovely kimono. Feel fabulous, feel sexy – be a temptress for the day! Wear dramatic makeup during the day instead of the night – be different, be bold! Pretend you are makeup artist Pat McGrath and allow yourself to go overboard with winged eyeliner or wild colors. Prepare a set of hors d’oeuvres in pretty platters and set them on your coffee table. Snuggle in a cashmere blanket and silk pajamas, and watch Sex & the City for an entire evening. Redecorate your room. Go to…