A derisive and crass expression, commonly used to convey a notion of self importance and or victory with total disregard for others. Common reactions are less than positive, as some people struggle triumphantly with the development of a sense of humor. It is typically used in a sarcastic fashion or when one is just plain killing it.
me- ha! totally didn't pay for that drink.
them- they forgot to charge you? you should pay for that.