Mine has to be Microsoft too because of aggressive bribing they did/do to destroy the chances of many countries and schools using Linux, and how they fragmented the unix ecosystem. Linux has always been a better choice and as soon as it was chosen, Microsoft would give significant bribes to the decision maker stupid enough to not realize that the entire organization is now hostage to pay for support for the end of their life as the os is too much of a garbage to maintain sometimes without secret insider knowledge.