https://motherfuckingwebsite.com/

And the drivatives: http://bettermotherfuckingwebsite.com/ https://bestmotherfucking.website/ https://perfectmotherfuckingwebsite.com/

Oh, but that would mean the website is just providing you information. That's not the goal--we need to fingerprint your browser, track you, and serve you ads. Quid pro quo -- if you want to know this recipe for cookies, we need to know your purchasing behavior for the past six months. Btw, can I use your location? How about notifications, can I send you those? And for the best experience, you really should be using the app. It's actually just the website wrapped in an iOS/android package, but it lets us track you more effectively. Thanks!

I find it's rarely JavaScript or css themselves itself but sites that load 400 different things from 100 other domains. Sites that quit loading all this other shit work and perform great even if they're fairly large and complex.