This question was inspired by my hatred of Temporal Anti-Aliasing which, in many games nowadays, is poorly used as a performance bandaid. On lower resolutions it will smudge and blur the image and certain bad cases of TAA will cause visible ghosting.
Yet in spite of all this, certain games won't let you turn it off or have hair/fur/foliage look like dogshit without it so sometimes I still use it.
anything proprietary