It's okay to have an "off" day
Sometimes Tuesdays can be just as bad as Mondays, head-fogginess-wise. If your Monday is especially bad, Tuesday may feel like a new chance to get your feet under you, but if everyone and their cute little puppy has had a day-long start on the week, while you're fumbling to enter your iPhone password, Tuesday can be an equally large beating.
Today was one such Tuesday. Today, my meetings expand well beyond my standard work hours, all the way until 8:30 p.m. Today, I woke up on the wrong side of my alarm clock, and it was everything I could do to just put on something that sort of matched. Today, it's hot, real-life H-O-T in various places across the country, and most of us are trying to figure out how to wear as little clothing as possible. What you do wear needs to be functional for both an office space (casual though it may be) and for the sweltering, 10-minute walk to lunch. Hence the layering.
I'm wearing a J.Crew Factory "Perfect Shirt" in plaid that's 100% cotton (definitely not flannel), a J.Crew tank, Madewell necklace, $12 H&M pants and those awesome Madewell sandals that just.go.with.everything. Obviously. In the heat of summer, use long-sleeved shirts as jackets that make you appropriate in the A/C, but chuck them in your purse or backpack for a casually-chic outfit that won't make you sweat bullets.