[Grammar] What are you thinking?

[monawin]

I was wondering why this sentence say 'What are you thinking'.

: What are you thinking, sleeping on the sofa at the Met?

 

[Raymott]

Without any context, it's only possible to guess.
"What are/were you thinking?" often means "How do you justify what you are doing? This seems to be unusual behaviour. What is motivating it?"

 

[Rover_KE]

Welcome to the forum, monawin.

Where did you encounter this question?