I'm sure we all have those days when we want to put as little effort as possible into everything we do. I do believe that such 'mental detox' days are not bad, but, on the contrary, necessary in order to stay sane, calm and collected for the days to come. On such days, we end up taking the most minimalist approach to dressing, choosing comfort over trends and statement pieces. In my opinion, the easiest way to dress for those days is going with one basic color for the entire outfit (such as black, beige, gray or white) and adding one stand-out accessory to give an impression that you still care (and I'm sure you still do). Try pairing your basic ensemble with a printed scarf, a pair of bright shoes or a colorful bag and that'll definitely get you through the day without raising any inquisitive questions.
Sweater: LOFT; Pants and Scarf: NY & Company; Boots: DV by Dolce Vita