Neat little tip via Reddit.

While watching a YouTube video type 1, 2, 3 etc. and you’re taken to 10%, 20%, 30% of the video.

Sadly it doesn’t work in full-screen nor on embedded videos.

Google is known for including these neat little features into its products and patiently waiting for users to discover them. The last one that comes to mind is playing Snake while watching YouTube videos.

Anyhow, try it out.