It depends on the context. So it's important HOW you say it actually.
If it is takes someone too long to do something, you can say "hadi canım, hadi!" to tell them to hurry.
If someone says something unbelievable, or makes a joke you can't believe, you can say "hadi canım!" to show that you don't believe what that person says. It's like, "come on, don't try to fool me"
If you're very surprised after you heard something, again you can say "hadi canım!"