When it comes to marinades, there are a few components that help ensure tender, flavorful results. Let's dissect this recipe as an example:  Greek yogurt - like vinegar and citrus juice, Greek yogurt has an acidic component that's key to tenderizing the chicken. So the chicken cubes don't turn to mush, only marinate up to 8 hours.  Flavor Enhancers - Feta cheese, garlic, rosemary, mustard, scallions all infuse flavor into the chicken. Aromatics like onions, garlic, and scallions are an important addition unless you have an aversion to their flavor. Salt and Pepper - Salt, like wine and alcohol, is a flavor enhancer. Do not omit unless you're on a sodium-restricted diet. I typically add half the amount of pepper as salt, but this is up to your palate's preference.