Dr. Malpani offers some insight:

For one thing, doctors in hospitals are very busy and they often just don’t have time for the common pleasantries which we take for granted in our daily life. Many of them are brusque and down-to-earth because they need to get on with their serious job of taking care of their patients, and they simply cannot afford to chit-chat with patients or their relatives. This is why they put on a shield which protects them from having to spend too much time with one patient. They cultivate an aura of superiority and aloofness to allow themselves to accomplish their tasks effectively.

They are usually accompanied by a retinue of assistants and juniors – and they often spend more time talking to them than to patients. Since nurses and juniors are deferential and respectful, patients are expected to toe the line and follow suit.