A postman delivers a registered mail letter in a native American reservation. Later that day he returns home and passes the same reservation. All Indians are dancing in a row, holding their war axes, their skins painted red and they are shouting: ooh-ooh-ooh-ooh-ooh.
The postman asks the medicine man, who is standing a the side, what is going on.
He answers: It is because of that letter you delivered earlier. It said their social security payments will be stopped if they continue to refuse the jobs they are offered.