If you describe someone, especially someone you think is superior to you, as gracious, you mean that they are very well-mannered and pleasant.

If you describe the behaviour of someone in a position of authority as gracious, you mean that they behave in a polite and considerate way.

You use gracious to describe the comfortable way of life of wealthy people.

Some people say good gracious or goodness gracious in order to express surprise or annoyance.