I Must Diff - You say 'I Must Diff' when you're so fed up you're ready to

You say 'I Must Diff' when you're so fed up you're ready to start a fight.

'I Must Diff' when my friend said my drawing looked like a cat threw up.

'I Must Diff' after my teacher said I was 'not trying.'

'I Must Diff' because my mom said I was going to get grounded forever.