Some days, you just don't feel like it. Even self-dubbed glamour junkies sometimes wake up not feeling up to wearing an elaborate ensemble. On days like yesterday when I had a ton of stuff to do, I try to not look like a slob-kabob-and-a-half by at least pulling myself together with a nice knit t-shirt and sweater. I firmly believe that just because you are going casual for a day does not mean that you have to drab yourself down for the sake of comfort.
Those days when you are tired, the key to keeping your outfit from looking blah is the right accessories. I happened to choose two of my favorite rings, a nice belt and my go-to "I want to be comfortable, but still cute" lace Keds, which bumped up my outfit from blasez black and navy with a little ornamentation. I highly suggest knits by both Alexander Wang and Rick Owens. While expensive, they just feel so luxurious and don't fall apart after years and years of wear (I've had them since my junior and senior year in high school, respectively) and they were worth their weight in gold. Even if the aforementioned designers are not at an obtainable price point, J Crew and Gap have excellent quality knits that are just as comfy and can easily do the trick for a "lazy day" ensemble-- as my mother always says, it is not the price of the piece you are wearing thats important, it's how you wear it.
As a final note, on the days when you just don't feel up to the task of styling an ornate outfit for yourself, I suggest not reaching for leggings and a t-shirt, but jeans and a loose t. It's a classic look and you can't go wrong with it (You can however, go wrong with leggings if you pair them with a short t-shirt and fail to realize that they are not opaque before leaving the house-- not cute, ladies!). In this more "appropriate for the public" ensemble you'll feel more confident to confront the day and the tasks you have ahead of you, while still not sacrificing your comfort for the sake of style.
Sweater: Rick Owens Lilies. Top: T by Alexander Wang. Jeans: Rich and Skinny. Belt: Hermes. Shoes: Keds. Rings: Target and Alexander McQueen.