Internet Explorer has been the designer's nightmare, pretty much up until version 10, which is available with Windows 8.
The reason being that IE failed to support so many of the web standards, so that you created your nice web page, which would look more or less the same in Opera, Firefox, Safari, Chrome... and then you had to make it work in Internet Explorer, often by adding extra code, hacks and extra style files.
One can safely say that Internet Explorer held back the development of the Internet for years. Version 10 has caught up with most of it, not before time!