Food is the great equalizer of Thailand. Though the country is very stratified in terms of class, Thai street food seems to bring everyone together. Some of the best Thai Food in the country can be found at these small unassuming stands, and it's not uncommon to see luxury cars lined up next to a particular vendor, and people in business suits eating next to taxi drivers on small plastic stools on the sidewalk.
Many tourists are a bit shy of the street food, thinking it unhygienic, or of low quality, but don't be fooled by the small cart. Thai people take their food very seriously, and most of the ingredients used are fresh from the wet market that day, making them probably fresher than most of the stuff in the supermarket. That's not to say no one has ever contracted a case of “Bangkok-Belly” from a street vendor, but you really will miss out on some of the best food in the world if you don't give them a try. A good tip in finding a good Thai street food is to simply watch where the Thai people eat, and a little stall crowded with Thais is a good indicator of great food.
Thai Street Food is very inexpensive, with most dishes going for between 20 and 40 Baht (.50 to $1 US), and don't worry about the language, a smile and some pointing will do you very well. Some of my favorite street food includes Gwiteow Moo Deng (noodle soup with red pork slices), Som Tam (spicy papaya salad), Pad Thai, Satay Gai (grilled chicken skewers with peanut sauce), and of course Kluey Kaek (fried bananas).