My family came to the US like 20 years ago and I can't remember a day when we didn't have yogurt. Whenever my family goes on a long trip, we have to do two things: get a neighbor to water the houseplants, and get a yogurt culture when we come back. In South India, it's traditionally eaten with rice as the last course of a proper meal. It's the perfect antidote to hot curries and pickles that come in the main part of the meal, so a meal isn't complete without it.
Young children usually start off eating solid food with a mix of rice and yogurt.
In rural areas, families make yogurt with their own cows and buffaloes and might pick a particular one for yogurt because taste varies between milk produced by different animals.
Going to relatives' places you'd notice two differences in their cooking: the way they made their chai (brand of tea, how much sugar, cardamom or not) and the texture and tanginess of their yogurt.