There are many reasons why a person could be rude. In Nepal, people are so much stressed out because of their social life (too much of it) that they don't have any energy left to be polite to someone they don't know. Most parents themselves are not in right state of mind to teach their kids. And kids only learn from their parents. And the trend continues....The trend that elders are always right, it is considered wrong to question our cultures, etc etc....So people become frustrated unknowingly and don't have enough smiles on their face leftover to show it to people.... and hence they act rudely.