Udipi Ltd.
I detest Udipi restaurants in Mumbai. All that matters to them is cash...lots and lots of it. They're least bothered about customers. Besides food, what's distasteful is the attitude of the waiters.
I remember going to one near Andheri station (W). The name's Nootan. Just 2-3 shops past McD. I was trying to place an order, and (as always) the waiter was in a hurry. He started moving before I could finish. When I protested, the answer was "aap ne ek order diya, wo meini suna na!" ("I did heed to your previous order!").
Another annoying practice is switching the water glasses. If you've not been gulping, busy in a conversation or something, the glasses shall be switched.
The problem is, when you're in Mumbai, every once in a while, you do end up with no option but to visit one of these Sai *'s.