"Just as the hairs on a violin's bow rip and get fuzzy over time as you move it back and forth, the same thing happens with your nails," says Miss Pop. "That motion causes tiny tears and splits in the nail that can turn into full-blown cracks and slits over time." Instead, she recommends just filing the nail in one direction. "I admit it's a slower process, but you just have to be more deliberate and purposeful with each stroke. I promise this will give your nail a smoother and more refined finish overall."