Ballmer created an indescribably toxic culture around reviews with his David Welch inspired "up or out" and "fire the bottom five percent" policies. Stack rankings were more like knife fights than honest appraisals of people's abilities and contributions. Teams used to deliberately hire underperformers so they could fire them, thus shielding productive people they would otherwise have to get rid of.

I'm not going to get started on his miserable technical leadership. Things more or less just happened under him, he didn't seem that involved in the quality of what was being produced.

Microsoft is well rid of him.