There are lies, damned lies, and statistics.
-- attributed to Benjamin Disraeli.
I'm a great fan of Darrell Huff's perennially best-selling How To Lie With Statistics. The title is deliberately ironic, as the book is really about how not to be be misled by the misuse of statistics.
One of the most egregious examples of seductively bad reasoning in economics is the Laffer curve, particularly as the central plank of Reagonomics and supply-side voodoonomics. Not surprisingly, the Wall Street Journal loves it (they know their audience...), as PZ Myers describes.
See also Brad DeLong, and Crooked Timber on throwing out outliers like Norway.
 Amusingly, this too is an example of lying with statistics. Back