One word: waterproof. Mascara streaming down your cheeks is never a good look, but forget good looks — it's messy and irritates the delicate eye area, making for more problems (and warranting more concealer) later on. The problem is that companies can claim they're waterproof until they're blue in the face, but they run for the hills at the first sign of moisture. The only mascara we've found that really lives up to its promises is Fairydrops Scandal Queen Mascara ($24 at Sephora). The unique formula is made of fibers rather than pure pigment dye, creating tiny tubes around the lashes that only come off when you want them to. It sounds bizarre to non-beauty junkies, but trust.