The "new" Reddit completely kills my 12-inch MacBook when I load a page, and it still feels sluggish afterwards. That pile of garbage literally loads more code than content.

YouTube's crap navigation system is the same - if you click on a video it will actually load it & update the page within the client using JS, and in my case it's considerably slower than just loading the server-generated page from scratch. I often find myself opening videos in new tabs (and closing the old ones) or hitting refresh as soon as the URL bar is updated just to avoid this shit because fetching & loading a brand new page is actually faster than their so-called "improvement".