Why does Internet Explorer have to be such a PITA?

Question

It seems that, despite having once been the standard browser, IE fails to adhere to modern standards, requiring devs to:
1. Add extra code, in numerous situations, in order to provide compatibility
OR
2. Disregard its existence, entirely, potentially sacrificing any potential guests, who choose to use IE.

Answer 1

I.E was built in the day when there were no search engine standards, and serious Web applications were few and far between. Modern day I.E is still built on those very old foundations, and finding ways to update I.E without effecting the crumbling supports is hard, meaning progress is slow. Adding New features, like html5 support could be very bad for the infrastructure, and updates come slowly. Therefore, due to I.E's issues, it is slowly being driven extinct as newer search engines built on more easily adapted platforms take over the market. (Google, Safari, Cough Cough)