Greasy Fork is available in English.
This used to display ratings bar on YouTube thumbnails, but Google has blocked how it gets its data. I'm disabling it for now in case people still have it running.
< Feedback em Youtube Video Ratings Bar with Power Meter (DISABLED)
works very well - make sure to update Greasemonkey
This script is awesome. The first time though, it did nothing (I'm using Windows 7, Firefox 34). Then I checked my Greasemonkey version and it was old (1.x). Updated Greasemonkey to the latest (2.x) and this script worked great!
I hate getting tricked by fake youtube posts that give a popular title, but then instead of showing the actual video, it just has some person's lame commentary.