My most hated at the moment? Those ads that hijack page scrolling and don't let go until you've scrolled the ad past. Wouldn't be a huge problem if it didn't totally fuck up my browser's scrolling functionality and lag things out.
Disable scripting, use wallabag to read the content (or a similar readability service), just leave the site and let them rot or find the contact info and tell them why you hate them now.
