You know the complexity of web technology is getting out of hand when every website needs some special treatment. Imagine driving a car if you had to change the engine slightly or replace wheels every time you turned a corner and entered a new street? Browser development is a lot like that these days.
Nearly every modern browser has site patching features, to grease the wheels where the nuts and bolts of standards are exposed to the unpredictable elements of the web:
Update Edit (4/24/2014)
Url is now at http://dev.opera.com/blog/opera-s-site-patching/