If I could, I'd have an award for the pyjama ladies who sport their colorful do bo outfits everyday and to go market to hawk street foods and snacks. When you go to Vietnam, you're sure to find your favorite gal(s) -- whether she's selling fruit, a bowl of noodles, sticky rice, or che sweet soup. Maybe you only eat her stuff once, fall in love with the morsels, and look for her again for her daily route or at her stall in the marketplace.
There's something reliably sweet and calm about the pyjama food vendors who in many ways are the life blood of Vietnam's food culture. They're savvy business women, good salespeople, and usually interested in conversation.
I hope Vietnam never goes the route of other Southeast Asian countries and put the street vendors in mall-like hawker centers. I appreciate hygiene just like the next person but I've never fallen ill from Vietnamese street food (knock on the baby plastic chairs that you sit on!). Hawker centers in Singapore are convenient but there's some soul missing.
Cathy at Gastronomy has a great posting on her favorite lunch lady in Saigon. Check it out!