I could care less/ I couldn't care less (context dependant)
Sarah: YOu know, my sis an her kid will be visiting us tomorrow, and it gives me a headache thinking about all the hassle we'll have in the house...
The d00d: ICCL...
Acronym for "I could care less", an even more dramatic version of IDC or idgaf. A way to tell boring people off.
Er_zel_a: omg guess what I have exciting news for you!! :D