They never do. Western movie and TV show makers. The India they show does not exist. Not the background music which they imagine is how Indian music sounds; not the accents which are unintelligible to Indians, heaven alone knows what the audiences in the West make of them and certainly not the locales they show. In more than a couple of western TV shows that purport to show call centers in action, the location is usually so outlandish as to defy common sense. Imagine a BPO office in the middle of Delhi’s Chandni Chowk, with hawkers peddling street savories like samosas and gol gappas walking right in front of the building and a cow peering in through the glass door!
And the accents that they show being deployed by Indians speaking in English are a figment of somebody’s extremely weird imagination. Admitted that a lot of Indians speak accented English; but the accents pertain to a region or community, say Punjab or Tamil Nadu or Bengal. In most American or English(British movies), the Indians speak in a strange sing-song accent, sounding like bells going off somewhere even as they actually swivel their heads around their torsos while doing so.
Another constant is the presence of a scheming and manipulative Indian who is constantly trying to throw a spanner in the works and the young virtuous white man with an exasperated demeanour who teaches older but obviously inferior Indians how to stand up for their rights and do the right thing. Then there are constant digs about the eccentricities of Indian people-their many festivals, their rituals, their superstitions, their funny institution of arranged marriage, and their sheer inability to understand the nuances of western culture. Of course there will be a compensating ode to wholesome Indian values like having close-knit families, immense faith in their gods and of their ability to have a good laugh in very trying circumstances. This to dispel the notion that the kindly westerner has any kind of bias or prejudice towards the great Indian people.
Really the craziest of Bollywood movies with the lowest of budgets get the American and Europeans mannerisms far better. A white man in most Indian movies is recognisable by the way he talks, dresses and displays attitude, even if it is an Indian masquerading as one, because the effort is usually based on an honest understanding. Not so in Western movies where they get foreign actors(even if they are of Indian origin) perform to their own bizarre notions of how Indians behave. The script writers of course don’t know whether India is in the tropics or on the North Pole.