Have you ever gone shopping and fell in love with a pair of shoes that you bought them in 2 colors or even worse you loved a top so much you bought two in different colors? If so, you need to go back and return one of them immediately!! Unless this is a tank top which you are layering with or a pair of panties in a few colors then you just committed a style crime! I admit it I was guilty of this at one point too, however I have learned this creates a very boring wardrobe. Your wardrobe should be full of one of a kind unique pieces with basics mixed in, but you do not need that flower shirt in white and black just because it looks good on you. If you start doing this a lot you will start to feel as though you are wearing the same thing all the time and who wants that. Same thing with heals pick one color do not buy; one black, one brown and one red etc. You want to have variety in your closet so when you feel the urge think about what you have in your closet; ask yourself what are you missing? or what color do you look best in? Chose one and walk away from the rest! :) Trust me on this one you will thank me later!
In the case of style "One of a kind is so much better than two of a kind"!