Yes, wee suppose it is only fair that wee answer that question. Even leaving aside our intense dislike of Microsoft, the simple truth is that as a browser, IE just isn't up to scratch. It is a giant pain in the arse. The problem is there are literally millions of websites out there, built using many languages, and there are a vast number of different browsers out there, all of which have to read and interpret these languages in order to display these sites correctly.
For this reason, there exists a wonderful organisation known as the World Wide Web Consortium who develop standards for these languages. For instance, using CSS (a web design language) one can write "margin-top: 10px" to give something a top margin 10 pixels high. It is thanks to the W3C that all browsers can interpet such instructions in the same way.
Well, indeed! How lovely it would be if all browsers worked exactly the same. How VERY MUCH easier the job of web designer would be if one's lovely design looked identical in all browsers. No so much. Internet Explorer, in typical Microsoft fashion, does not adhere to W3C standards. Whether this is due to ineptitude on the part of the browser's designers, or just arrogance, is not relevant - the consequences are.
CSS is by far the worst affected area. It is a phenomenally useful, simple and powerful language. Introduced in 1996, with version 2 (CSS 2) following in 2001, it revolutionised web design... whilst also revealing IE's many failings. Designers had to resort to all sorts of tricks in their attempts to get the idiot browser to cooperate: using non-standard, gibberish code - ruining otherwise clean and efficient builds.
The issue is compounded by Microsoft's domination of the computer world - and as a consequence, the browser market. All PCs come with IE installed on them, so the vast majority of people stick with it and never try any other browser. This means that, as much as we designers want to say "f*ck it, the site works fine in every other browser out there", we can't - most people aren't using those other browsers.
Ignorance of web standards is by far IE's biggest crime, but it isn't the only one. Compared to more robust browsers, in particular Firefox, Safari and Opera, it is not anywhere near as secure. It allows websites to install programs and control your browser - taking the power away from you and giving it to unsafe websites. It is also more prone to crashes - and, due to its tight integration with Windows, this can means that it takes the rest of your computer with it when it crashes. Great.
Now, to be fair, Microsoft is upping its game. IEs 6 and below are just appalling, but fortunately, few people use them any more (IF YOU ARE ONE OF THEM, UPGRADE RIGHT NOW). Later versions are better(although all of the 'new' features were stolen from other browsers, whose users had already long since been enjoying them). IE 7 corrected some of the problems, but not all of them, which was almost worse. Whereas before, designers could say "use these design instructions if you are a normal browser and these if you are IE", they now had to say "use these design instructions if you are a normal browser, these if you are IE 6, and these if you are IE 7. So much for clean, efficient code! IE 8, in comparison, is a breath of fresh air. It is NEARLY completely CSS 2 compliant. Many sites now render exactly the same in IE 8 as they do in Firefox or Safari, give or take a few bugs. (Always, there are bugs with IE).
Simply put, the competition is light-years ahead, and always will be. Yes, IE 8 now finally understands CSS 2 - but the world has moved on. CSS 3 is being developed (and wee are very excited about it!). If you view any of the sites wee have built using a browser like Firefox, Safari or Chrome (all of which understand CSS 3 already) you will see a number of differences - tweaks to the design that create a more polished site. CSS 3 is still not understood by IE - not even IE 8. Take this very page. If the headings have shadows and there's a nice, rounded border with a shadow surrounding this text, you are using a decent browser. If not, maybe you should be...
This has been a very long-winded rant, but wee hope you have learned something, and will stop using IE. Our personal favourite is Firefox, for many reasons - give it a go and see what a difference it makes!