YouTube changed the look of its subscriptions page a few years ago, moving from a grid layout to a single-column view that requires a great deal more scrolling to view its wares. If you've been pining for the good ol' days of the My subscriptions grid view, there is an easy fix for Chrome and Firefox.
For Firefox, install the YouTube Subscriptions Grid add-on. After installing it and refreshing your subscriptions page, you'll see a grid layout with a lot less wasted space. On my 13-inch MacBook Pro, which features a 1,280x800-pixel screen resolution, the grid goes four thumbnails wide. With some quick math, I would estimate that this add-on results in a 75 percent decrease in scrolling when browsing my YouTube subscriptions. In addition to the thumbnail for each video, the title is displayed along with the author, how long ago it was uploaded, and the number of views. The only piece of information that goes missing from the default, gridless view is a video's description.
For Chrome, you'll need to run this user script. (Just download it to your PC or Mac and then drag the file into your extensions page to install it.) After it's installed, refresh your subscriptions page and bask in the glow of your new grid view. It looks similar to what you get with the Firefox add-on, but the author information is missing from the grid. Also, it keeps the four-wide grid layout no matter how you adjust the size of your Chrome window, whereas the Firefox add-on drops a column of thumbnails as you narrow your browser window.