Potomac Day Spa, operating out of a cute little house in Potomac Village for more than two decades, has quietly closed its doors. “The rent here is just crazy expensive, and we had been struggling for a long time,” says owner Angela Hay, who bought the spa four years ago and shut it down last Saturday. The business had little walk-in traffic, Hay says, and it’s been increasingly difficult to compete with larger operations like Red Door and the new Woodhouse Day Spa on Rockville Pike. “The older people liked our quaintness, but the younger people like to go to places that are trendy,” Hay says. “I just couldn’t keep pouring money into something that wasn’t going to survive.”