Sweat is a summer certainty. You can swipe that deodorant twice, put your hair up into a bun, or wear as little clothing as possible — still walking outside will have you dripping in perspiration within minutes. So, on the hottest summer days, it can feel like putting on a full face of makeup is a total waste. Why dedicate time to get that eyeliner just right, only to have it melting off just a few short steps out in the sun? It's pointless.