The place was bright and loud and packed. The waiter came over and we each ordered pad Thai—enough like pasta to assuage my father, who would rather have been at a red-sauce joint—plus a bowl of tom yum soup for me, which I chose because it included shrimp. The soup arrived first, a brown crock of cloudy broth with a few mushrooms, a sprig of cilantro, flecks of chopped something (lemongrass and Kaffir lime leaf, I would later learn), and exactly one pink shrimp. No matter; it was the broth that floored me. It had an unfamiliar sourness that was round and sweet, but it had an intriguing fishy flavor, too, and a beautiful citrusy fragrance. The pad Thai arrived, a teetering heap, tangled with stir-fried egg and scallion, sprinkled with peanuts, all of it strange to me and addictive. I remember looking around to see how the other diners used chopsticks, and then back at my quiet family who twirled our noodles around forks.