Hi, how are you?
Can be a nice thing to say if you say it to a friend or a loved one, but inappropriate if you say in response to a police officer that asks you how high are you?
Example:
Police officer: How high are you?
Some random idiot: No officer, you're wrong! It's Hi, how are you?
Police officer: How high are you?
Some random idiot: No officer, you're wrong! It's Hi, how are you?