-你有冇搞錯呀- 英文點講 ?

1. You can't be serious !
較口語化&casual

2. Are you sure ?
跟1)比較下, 較formal

What's wrong with you?

這個句子應該最貼切

The most casual:
What the xxxx is wrong with you???
(xxxx is not allowed to write in public I think)

Or more polite:
what the heck is wrong with you?

應該是
Is anything going wrong with you

Are you crazy?
What's this all about?
You must be mad!
Oh, my God!
No, you must be joking.

你有冇搞錯呀的口語化是 (got damn)