Ballmer has a BAD case of "Not invented here". I remember reading a story about him calling out and mocking an employee in a meeting b/c they has an iPhone (this was around 2008 I think). First off it's a VERY GOOD IDEA to use your competitors products if only to see how they stack up (Spoiler: They blew away MS's mobile offerings in 2008 and still do to this day). Second, what a way to make all of your employees yes-men who live in their own world shut off from what was happening in real world. He was douche all around from what I can tell and him leaving is one of the best things that could have happened to MS. Ballmer took over MS soon after I really got into computers and let it stagnate (XP/IE6) which lead me to switch to Linux/OSX and I've never looked back. I'm not saying it's all his fault but I think he was extremely influential in decisions that ultimately pushed me away from MS.