Neither have I, but when I am awaiting my departure turn and I hear the tower controller at my home airport say, "Cobra 1, wind 280 at 12, cleared for takeoff, you are cleared to 15,000 feet" (our airport is 420 feet above sea level) and then I watch this aircraft on full afterburner take off and then go vertical, I think to myself, "is our government really PAYING those pilots to fly that aircraft???"
edit: added airport elevation for full effect