Of software, used to emphasise that a program is unaware of some important fact about ITs environment, eITher because IT has been fooled into believing a lie, or because IT doesn' t care. The sense of "happy" here is not that of elation, but rather that of blissful ignorance. "The program continues to run, happily unaware that ITs output is going to /dev/null." [Jargon File]