I was traveling through India with my sister, and she got terrible food poisoning. I put her in a private hospital, where she was given incredible service and recovered within a four days. The hospital bill was only 8000 rupees, or ~$150. My sister told me of one nurse who gave her exceptional care, so I tried to give that nurse a 5000 rupee ($100) tip. Without a moment of hesitation, she flat-out refused. Her response brought tears to my eyes -

"Sir, this is my duty. There are poor people right outside, your money would really help them."

As I talked to my relatives about what I experienced, I learned that Indian medical staff see their job as their dharma (duty), a belief that stems from their medical training and originally from the Bhagavad Gita, a religious text that is central to Hinduism. If I had to state a particular reason for the quality of Indian medical treatment, that's what it would be - that they consider their jobs a sacred duty. When someone truly believes that their job is a sacred duty, they will do it with a passion that cannot be artificially reproduced by a huge salary or per-patient compensation.