Forget what your mama told you: At little Pho Hoa, it is definitely nice to slurp your soup. In fact, the sounds of slurping and lip-smacking are music to the ears of owner Manh Nguyen, as they are to any Vietnamese soup-shop proprietor. That's the way guests traditionally show appreciation for pho, a lovely noodle-and-broth-based meal in a bowl, eaten with chopsticks and porcelain spoons. So smile, and slurp it up. We promise not to tell your mom.