She actually spent money on her nails
Ew! Look, lady, just because you work with greasy machines all day doesn’t mean you shouldn’t clean your fingernails! In fact, that’s where a lot of bacteria can grow! Leaving that much filth under your fingernail could potentially mean catching some exotic disease when you accidentally bite them.
Oh, wait, please disregard everything we just said. It turns out that this lady paid to have her nails done this way. She gave clear instructions to a manicurist to paint the underside of her nails a dark color. Her goal was probably to trick people into thinking that she was a mechanic. What a weird thing to do.