In a medium bowl, combine mayonnaise and sour cream. Whisk until smooth and well-integrated.
Add lemon juice, Dijon mustard, and garlic powder. Stir until fully incorporated.
Gently fold in the chopped fresh herbs, being careful not to bruise them.
Season with salt and pepper to taste, starting with 1/4 teaspoon salt and a few grinds of pepper.
If using any optional ingredients like honey or minced shallot, fold them in now.
For a thinner consistency, add buttermilk or water a teaspoon at a time until desired texture is reached.
Cover and refrigerate for at least 30 minutes before serving to allow flavors to develop.