Thai food is built on the principle of balance — the four flavours (sour, sweet, salty, spicy) must be in equilibrium in every dish, and the fresh herbs (Thai basil, kaffir lime leaf, galangal, lemongrass) are not garnish but structural. Som tum (green papaya salad, pounded in a mortar with palm sugar, fish sauce, lime, and dried shrimp, and fresh chili in a quantity only described honestly) is the dish that the whole country eats and that each region prepares differently enough to constitute four separate dishes. Pad Thai (rice noodles stir-fried with egg, bean sprouts, and dried shrimp, finished with tamarind and lime) is the national dish by international reputation but the street stall version (eaten on a plastic stool with a beer and street noise) is the correct context. The night market culture — from Bangkok's Yaowarat Chinatown to the Sunday Walking Street of Chiang Mai — is Thailand's most democratic food institution: mango sticky rice, grilled corn, and satay at 11pm for the price of a coffee. Cha yen (Thai iced tea, sweet, orange, milky) and the various fresh fruit smoothies manage the heat. That's where it gets good.