i thought you knew that - A Southern person says this with a hair toss and sometimes a

A Southern person says this with a hair toss and sometimes a curse word. It's like they're saying, 'You should have known this already.'

'I thought you knew.' (hair toss) 'You should have known.'

'I thought you knew.' (cuss word) 'You're the dumb one.'

'I thought you knew.' (hair toss and cuss word) 'You're the worst.'