To be used when someone doesn't give a fuck about you; to be ignored.
Boy A : Today's really tiring.
Boy B : Yeahh, my school ends at 5 o'clock. Damn!
Boy A : Hahaha that's sad! Mine's at 2!
Boy C : Hey guys my guitar cost 2.4k.
Boy B : Yeahh, that's sad. Good for you...
Boy C : Hey! Don't mark me please!