A more badass way of saying "I'm sick and tired of repeating myself, get it through your fucking head". May also have implications of "are you calling me a liar?". From the Bruce Willis and Damon Wayans movie "The Last Boy Scout".
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".