[Fyron]

There are many reasons: strong arm tactics; abuse of OS monopoly to drive countless competitors out of business through extremely anti-competitive behavior; being behind everyone else by years, even decades, on adding "new" features; making a browser that has never supported HTML or CSS (flagrant disregard for standards of all sorts); integrating IE into the OS (very bad idea on every level; running a browser in kernel mode is probably the single stupidest thing MS has ever done); all future updates to IE will be parts of service packs for XP and later, so users of older (better) versions of Windows are screwed; ActiveX (terrible, terrible software); product activation (this does not stop piracy by even 0.00001%, it only harrasses legitimate customers; I fear what Longhorn will do to people...); XP (speaks for itself); making products that are so full of security holes and _not_ patching them for years or even ever that it is not even funny anymore (there are a few dozen critical security flaws in IE that let a remote user run any arbitrary software on your PC that s/he wishes that have been well documented but never patched, for example); adding "features" like the ability to install software on a machine just by including it in an email and having that email opened in Outlook (yes, this was a fully intended and advertised feature, not any sort of bug); having the default priveleges for users of home OSes be administrator level; the fact that the majority of Microsoft's servers run BSD, not Windows Server, which just tells you that not even MS trusts their OS; etc. It is not because Microsoft is big or successful, it is because it is extremely evil and still has not figured out how to make an OS that is secure on a basic level.