I freely admit that I am swiping this from the nerd site toplessrobot, but this list and the reasons given are priceless! Give this a read thru and see for yourself.
http://www.toplessrobot.com/2009/07/the_8_worst_underoos_your_mother_ever_bought.php
http://www.toplessrobot.com/2009/07/the_8_worst_underoos_your_mother_ever_bought.php