Websites that change how the scroll wheel works, e.g. by adjusting the scrolling speed, using the scroll wheel to trigger animations or a "parallax" affects, or trying to make the scrolling "smooth" or "natural" (which usually results in not being able to scroll as precisely).
Seriously: if you are a web designer/developer, do not do this. I have literally never had my experience on a website improved by my scroll wheel doing anything other than move up and down the page at the speed I have set in the operating system. At best it's irritating because it's not behaving how I'm used, at worst it makes the website unbearable to use.