Can someone please explain to me what the big problem is with IE 6? Everyone talks about it like it is the worst thing in the world. I use FF and Chrome, hardly ever IE 8, so I apparently don't know about something. I hope this is the right place to ask.
I think there are two perspectives this comes from.
(1) Developer perspective. IE6 has a lot of... quirks. Things like "if an element has float: left, its left margin doubles." This means that things look different than in other browser, and it takes an inordinate amount of time to make them look good. (Or even halfway decent.) You can learn more about them here.
It's mainly because of compatibility problems and the number of security issues which IE6 has. Compared with new releases of Firefox and Chrome, IE6 is quite far behind.
A lot of the hate for IE6 comes from web developers. Since a lot of people still choose to use IE6, that means companies want their web pages to look good in IE6 as well as other browsers, which can be very difficult and stressful for web designers to have a similar cross-browser look when complex code and positioning is involved, not to mention the nasty alpha channel transparency hack among other things. I recently aided in the design of a website for a large company and we're still ironing out some issues with IE6. With newer versions of IE, things have been improved drastically however.
Another point of criticism against IE6 is the number security and stability issues. There is a massive number of security issues with the browser (144 Secunia advisories,184 Vulnerabilities), some of them being fairly critical.
The currently renewed hatred for IE6 (As we're all used to hating it for John-T and Arkaaito's reasons) is that HTML5, the newest version of the set of rules that define how HTML, the very language of the web itself, should work, isn't, and will never be supported by IE6. That means it's come beyond being an annoyance for web developers to write around (Yes, it's annoying, but it's doable. Annoying, though), and an actual hindrance to the web.
Now, IE7 and 8 don't support it either - however, neither do many browsers. This is a pre-emptive hatred, going after the worst offender - businesses who won't upgrade from the browser that's served them well for almost 10 years now.
IE6 is hated because it completely ignores accepted standards all other browsers adhere to, causing web developers headaches, and worse, and because it's one of the most dangerous pieces of software you can reasonably use. You're starting to hear about it more and more because it will soon be stopping progress, not just infecting PCs and annoying developers. A world without IE6 is a world where we're one step closer to seeing a version of the web not tied down with proprietary software like flash, one where playing a video doesn't take 80% of your CPU, but 3%. It'd be a better web, but we can't have it while IE6 still has a decent chunk of the market.
In all fairness, IE6 is quite old (released in 2001) and two version behind the current version. The reason why such a big deal is made about it is that it had a huge install base and it had an abnormally long life (IE7 was not released until 2006).
With huge numbers of people (particularity in business, government and institutional environments) not upgrading to Vista, XP & IE6 have hung on to this day. While for an individual the upgrade is not a huge deal, for an organization it is very expensive. A lot of corporations to this day continue to use IE6 because of the costs associated with upgrading (training, support, redeveloping or replacing various plugins that don't work in IE7, etc.).
So with about 20% of the users out there still using IE6, web developers need to code to support it (who would want to purposely exclude 1 in 5 users?). Other browsers that were common in 2002 when IE6 was new are forgotten about. IE5, Netscape and even AOL's browser are no longer even a blip in the usage stats so nobody cares about handful of people still using them. However, if Netscape 4 still had 20% market share, you would be hearing daily rants from web developers about how it sucked.