Here's the ever-quotable Judge Easterbrook, in an August case entitled Yindee v. CCH Inc., 458 F.3d 599, 18 A.D. Cases 417 (7th Cir. 08/11/2006)(via Michael Fox):

It is not enough to demonstrate that the employer was mistaken, inconsiderate, short-fused, or otherwise benighted; none of those possibilities violates federal law. See Forrester v. Rauland-Borg Corp., No. 05-4650 (7th Cir. June 29, 2006) (collecting authority); Pollard v. Rea Magnet Wire Corp., 824 F.2d 557 (7th Cir. 1987). Poor personnel management receives its comeuppance in the market rather than the courts.