Its getting annoying arriving at an approach frequency and getting told too slow down, hold or vectored to Timbuktoo whilst a citation or c172 is poncing in the area.
Unless the Citation or C172 is a survey, test or training flight and so Category 'Z' or you're in an emergency, the flight priorities are "first come first served" although ATC will endeavour to reduce the overall traffic delay sometimes by changing the order of play.
Those are the rules by which we - in civil ATC at least - have to operate. That's not to say that every air traffic controller agrees with them, though...
