You know, I'm Australian, and we have got the worst sense of humor. We are cruel to each other.

This quote is referring to the fact that Australians are known for having a very sarcastic, dry sense of humour. They often take jokes slightly too far, which can be seen as cruel to outsiders. It means that Australians are not scared to call out each other in a humorous way, but it can sometimes hurt people’s feelings.