There could be a whole thread on the ways in which Americans eat Indian food wrong, but for now, let’s confine ourselves to raita. Maybe somebody can tell me how raita really should be used. I don’t want to find myself caught beneath the withering stares of the cognoscenti, and trying to argue, “I don’ t care what y’all south of the Hindu Kush do, in these here parts, raita’s a soup!”
I’m not Indian, but I use it like tzatziki.
Raita is yummy!
I use it as a side dish. It’s a nice cool texture compared to the spicy and well-seasoned foods Indian cuisine usually contains. There are lots of regional variants…I am very picky on my raita and prefer only shredded cucumber in it with a little garam masala and seasoning salt. Others like tomato or other crap thrown in.
I lived with a friend from India last summer. She made raita (yogurt, cucumber, cumin) and used it as a side dish. It was so good. I miss cooking with her. Here my roommate eats a lot of chips, deep fried pizza, and cereal 
I like to use it as a dipping sauce for naan. Sometimes I think I could live on just naan bread and well-made raita. The same goes for pita and tzatziki, though. There’s something very basically satisfying about flatbread and yogurt.