Basic Dipping Sauce (Nuoc Cham)

Makes ¾ cup
3 tablespoons lime juice (1 fat, thin skin lime)
2 tablespoons sugar
½ cup water
2 ½ tablespoons fish sauce
Optional additions:
1 small garlic clove, finely minced
1 or 2 Thai chilis, thinly sliced or 1 teaspoon homemade chili garlic sauce or store bought (tuong ot toi)
1. Make limeade. Combine the lime juice, sugar and water, stirring to dissolve the sugar. Taste and as yourself this question: Does this limeade taste good? Adjust the flavors to balance out the sweet and sour.
2. Finish with fish sauce. Add the fish sauce and any of the optional ingredients. Taste again and adjust the flavors to your liking, balancing out the sour, sweet, salty and spicy. Aim for a bold, forward finish -- perhaps a little stronger than what you'd normally like. This sauce is likely to be used to add final flavor to foods wrapped in lettuce or herbs, which are not salted and therefore need a little lift to heighten the overall eating experience. My mother looks for color to gauge her dipping sauce. When it's a light honey or amber, she knows she's close.
Notes
Advance Preparation - This sauce may be prepared early in the day and left to sit at room temperature.
Variation - Use half lime juice and half Japanese rice vinegar for a less assertive sauce. Some delicately flavored dishes require this.