Best decision I ever made was installing an extension to get rid of the recommendations (they're such crap - I wish they would actually try to recommend me things with a high likelihood of me enjoying rather than whatever propaganda youtube wants me to see).
You can accomplish this without a dedicated extension by using either uBlock Origin's element blocker, or if you're handy with CSS, the Stylus CSS manager.
Using uBlock Origin, right-click the part of the page you want removed, select the "remove element" option, confirm it's got the right bits selected, and nuke.
Using Stylus, you'll be opening up the element inspector and finding the relevant selectors. Fastest option is to apply a "display: none important!;" directive to that.
Stylus is by far the more powerful and flexible of the two, and you can do far more with it if you care to. uBlock should be sufficient though.
