I so hate the videos YouTube shows me that I wrote a plugin to place a white box over videos called TubeGate [0], which I open-sourced [1]. It does keyword-based filtering so you can tell it to hide "sports", "politics", etc.

[0]: https://chromewebstore.google.com/detail/tubegate/aokfpmegea...

[1]: https://github.com/webcoyote/tubegate