I Know This - Used by people who think they're right and don't care about

Used by people who think they're right and don't care about what you're saying. Usually has bad spelling and grammar.

"I know this!" he said, even though he spelled 'know' as 'kno'.

"I know this!" she said, even though she wrote it as 'i kno' on her paper.

"I know this!" he said, even though he didn't know what the word meant.