I have a rudimentary always on reader mode: I turn off CSS and JS by default. Once I scroll past what would be the billion custom button gifs and menu items I'm left with beautiful, clean text.

I turn the stuff on on a per site basis when I want to use an actual web app, something like github, and every now and then I get an article that wants to fight me on it and my usual response is "well I guess you don't want to influence me with your words bad enough" and I back out. But it works 99% of the time exactly how I expect it to.