Okay troll, I'll bite...

Why does everyone hate microsoft?

For a large number of reasons, many of which have been mentioned already.

Where would computer technology be if it weren't for microsoft?

Farther ahead, I think.

I got started on computers back in '85 on a Wang PC (go ahead and snicker, ye of juvenile humour). It had a word processor that was far superior to any word processors that Microsoft produced until roughly 1993. My parents continued using that word processor until 1996, when they gave it to a friend. One version, no upgrades, 11 years. Ever heard of a Microsoft application with that kind of staying power?

Of course, who can forget that Apple started the GUI revolution (okay, some people assert that even they stole they GUI from someone else).

There is also the Amiga that died an unfortunate death. In 1985, a full 7 years before Microsoft's GUI became useable (Win 3.1), they had a colour GUI (Apple's was B&W, and PCs were still all text-based) that was capable of 3D graphics and video editing -- two things that Windows machines were incapable of doing until the early to mid 90s. NewTek (the company that writes Lightwave) released Video Toaster for the Amiga in 1990.

In the instance of software, Microsoft purchased SoftImage (a Canadian company that developed the then-visual effects industry standard 3D animation software). At the time, the hardware market in VFX was dominated by SGI. SoftImage got ported to NT, and they started writing the next-gen system (XSI). Under MS control, XSI was delayed, and delayed, and delayed. Eventually MS sold SoftImage, and XSI made it to the market a couple years ago. It has lost so much market share that it is nearly inconsequential in the same visual effects industry that it dominated so long ago. Since it was developed using MFC (development started under MS reign, remember), it only runs well on Windows systems (it uses very flakey replacement libraries on Linux) in a market that is moving increasingly towards Linux (my company in the process of buying another 80 Linux machines).

Computers would be more interoperable -- see the Kerberos incident.

People always bash microsoft but you don't see them making OS's or email programs.

On the contrary, they are. Linux, Hurd, BeOS, Plan9. There's four, and I've only scratched the surface. Heck, I wrote an OS for one of my classes in university. Hop on google, and you'll find a plethora of email clients. Furthermore, just because a person doesn't have the technical skills to write their own software doesn't mean they are incapable of deploring bad software.

Is it just because microsoft is mainstream and some people have a tendency to hate anything and everything mainstream?

No, it's because the people that don't like Microsoft have used something else, and are aware that better alternatives exist.

If microsoft weren't so huge I bet many of those same people would be saying f microsoft weren't so huge I bet many of those same people would be saying they love microsoft and calling Bill Gates their hero.

I used to like Microsoft and Bill Gates. Then I went to university and got an education.