GE had overly-inflated numbers. Basically, Jack Welch, the most over-paid CEO (ok, so maybe that of Enron was worse)... but Welch did receive the largest severance pay ever when he left. What did he leave? A zombie company that was left as a huge mess for the next CEO in line to clean up. Unfortunately, Welch focused on massaging the numbers for many years, and that only goes so far, especially when the stockholders and bondholders begin to wise up.
Meanwhile, you can read books on how great of a CEO he was and what amazing numbers GE pulled out of its hat when he was at the helm of the ship.
As for GM... there was some really fantastic stupidity there. Paying out dividends that were not-sustainable... and then taking on even MORE unsustainable debt, just to keep paying more dividends? WTF?! I bet Chanos fell out of his chair when his team were reading those financial reports at the end. This is basically the same shit Italian politicians have been doing, and they'll be expecting the rest of Europe to bail them out for it just like with Greece years ago.