This'll be fast and breezy. Firefox users can install them with Greasemonkey; Chrome users could use the native equivalent, but there's no point since Chrome can install Greasemonkey scripts as native extensions. However, Chrome seems to have some weird behaviour where it'll recognise it as an extension due to the extension being .user.js rather than just .js, but then complain that the website isn't authorised to install extensions—instead, download the file and then drag it into the Extensions window yourself and you'll be fine.
- The first one is by far the most fundamental one—if you want only one of these, it's going to be this one. It aligns the layout in the middle of the screen again, rather than the mind‐numbingly stupid setup they went gold with where it's aligned to the left with a substantial margin which puts it roughly in the middle provided you have the exact same screen dimensions as the designer and never, say, hit the button to make the video player larger because it's insultingly small on your 24″ WSXGA+ monitor.
- The second one fixes the link in the top-left corner of the screen so it takes you back to the subscription uploads list rather than to the awful list of videos on the Youtube homepage which prioritises featured videos and asinine recommendations over the list of people whose uploads I actually want to be told about.
- The third one puts the darkened stripe behind the video player back. This is me being picky - the page looked dull without it, I liked the contrast with the rest of the page and the way it focused my attention on the video.