In America, and perhaps in other countries as well, citizens in the middle of berating a government employee use one phrase more than all others combined:
"My taxes pay your salary!"
For some reason, it's been genetically programmed into many people that when they've run out of whatever patience they've allotted for this encounter, this phrase, a kind of verbal Hail Mary, flies from their lips, only to fail practically every single time.
It doesn't take a genius to understand the futility of this phrase. After all, do we honestly believe that the cop/postal worker/teacher/dogcatcher/etc. we're shouting at simply doesn't realize that some form of tax pays his or her salary? How deluded must a person be to think that this rude utterance will suddenly turn this civil servant around? If you're getting arrested, getting a ticket, or just getting mad at the teacher who failed your kid in biology, reminding them of the source of their wages is no more likely to improve the situation than telling them that they have a fat ass.