Usually when people say "get out of here," it's because they want you to leave. But in American English, when you say it in a certain way, it can mean something completely different.
get out of here 令人非常惊讶
A: I just moved to Washington, D.C. to start a new job.
B: Where are you from originally?
A: Dallas, Texas.
B: Get out of here! I'm from Dallas, Texas, too!
The phrase "get out of here!" is a way to say something is very surprising, interesting or totally unexpected. If you say it in an angry tone, it's telling someone to go away. Get out of here! get out of here! get out of here! But if you say it in an excited tone with a happy face, it's a friendly way of saying you can't believe what you're hearing.