The tritone has been a generally accepted part of Western music since at least the seventeenth century, and is now unavoidable. Those CAF’ers who advise not listening to music that contains a tritone would have to stop listening to Bach, Mozart, Beethoven, Gershwin, Elvis Presley, CCR, and just about every piece of music written between 1609 and now. If you want to restrict your car radio to Gregorian chant and Palestrina, go right ahead. Me, I’ll still be listening to the glorious riches of our musical heritage.