Once, YouTube thumbnails actually resembled the videos they advertised. Once, the recommended videos list was not a sensory overload of Photoshopped headshots and graphic overlays where every thumbnail looks like an Epic Rap Battle of History. You can return to that time, and replace the clickbait-y thumbnails with frames from the actual YouTube videos, with the Chrome extension Clickbait Remover for YouTube.
Install the extension, and tell it whether to grab frames from the beginning, middle, or end of videos. Clickbait Remover also lets you turn the ALL CAPS AMAZING MUST-SEE BANNED VIDEO TITLES! into lowercase or sentence case.
The result is a duller, less distracting set of recommended videos. Note, above, how you can finally tell what’s inside the videos, without hovering over each thumbnail for a preview. Now you can look for related videos that are worth watching, based on what’s actually inside them.
To hide a specific channel from your recommendations, use YouTube’s built-in menu. And if you want to see a high-res version of a YouTube thumbnail, enter the video URL into this form from Boing Boing.