The new Vizio TVs use motion smoothing to make the content you watch look smoother. It looks good for some content like sports but can ruin the feel of movies and series.
What is motion smoothing?
Motion smoothing works by increasing frame rate content you watch on TV. This is done by artificially adding extra frames between each real frame to keep content in sync with the display’s refresh rate, which can sometimes double or even quadruple the perceived refresh rate and «smoothness» of the image.
However, this doesn’t always look good, and often results in blurry images and nasty artifacts. Also, some people just don’t like higher refresh rates and prefer to disable this option.