I don't fucking care. - A loud and clear message that you're not going to take any m

A loud and clear message that you're not going to take any more nonsense. It's like a warning shot fired from a very angry person.

I don't fucking care if you're still wearing your socks on your hands.

I don't fucking care if your brother is still stealing your chips.

I don't fucking care if your teacher gave you detention again.