"If you sleep with dogs, expect to get a lot of fleas." That's another way of stating a childhood aphorism, "You are known by the company you keep."
Bank of America found this out the hard way when it was forced to pick up the tab, an estimated $20 million, for the defense of Angelo Mozilo, the former CEO of Countrywide (dis)Credit. Worse than the money, it is Mozilo's "reputational risk" that Bank of America will have to live with for a long, long time to come.
Here is a lesson for serial acquirers, if you buy company X and keep the CEO, that CEO becomes YOUR subordinate, for better or worse. (And few CEO's will sell their company without being "kept.")