There are countless ways to jazz up the basic recipe. Here are just a few:

Herbs: I’m partial to dill for yogurt dressing, but don’t stop there. Add finely chopped tarragon, cilantro, parsley, chives, or mint, separately or in combination.
Chile + lime: Swap out lemon for lime, and fold in a minced chile pepper.
Tahini + sumac: Add a big spoonful or two of tahini and dust with sumac. Serve with everything.
Roasted garlic: Stir in three or four cloves of roasted garlic that you’ve smashed and smeared on a cutting board.
Spices: So many choices here. Want to go more of an Indian route? Mix in freshly ground cumin seed, coriander seed, and a pinch of Garam masala. In a Spanish frame of mind? Try smoked paprika and freshly ground fennel seed.