I often set the playback-rate of youtube videos to something like 1.25 or 1.5 to get through a video a little faster without getting bored.
But sometimes 1.25 is a little to fast for my taste.
So i just went and had a look into the html and found that i can easily get any playback speed i want by running this snippet:
document.getElementsByClassName('video-stream html5-main-video')[0].playbackRate=1.125;
This sets the speed to 1.125.
But any rate will do: 0.69, 4.20, 6.666.
Doesn't matter.
It's kinda obvious that it will throw an error if there is not at least one element on the page with the classnames 'video-stream html5-main-video', but nevermind.
I then added this snippet into a browser-bookmark i can click anytime i'm watching a yt video and want to set the speed.
javascript:{document.getElementsByClassName('video-stream html5-main-video')[0].playbackRate=1.125;}
I tend to like assholes;
But not the person kind.