If we talk about the culture, no two cultures are same. The Indian culture is unique and has its own values, but America culture is not unique, its mixture of different culture. This is one of the major cultural difference that Indians are very much family oriented, and the Americans are individual oriented.
Exactly work culture, ethics is also different. In America people tend to work only 8 hours a day, they prefer only work at working time. Basically they go office at 8 AM and come at 4.30 PM.
But when we see this in India, people go office at 9 AM and they return at 10 PM, means people work more than 12 hours. It shows that people don't give their 100% at work place.
So time of working is totally different.