Idiom of the day - Couldn't care less

COULDN'T CARE LESS - when you are totally uninterested in something, or something doesn't matter to you at all, you say this

Eg.: Greg thinks we're all very interested in seeing him perform, but to be honest, we couldn't care less.
Eg.: When most people are approached with the topic of environment conservation, they behave as if they couldn't care less.
Eg.: "The teacher said she'll fail you in the exam if you come late one more time." "Oh yeah? Let her. I couldn't care less."
Eg.: Veronica said she couldn't care less about her husband's illness now that she's divorcing him.