Semantic overload
If the goal of a web page is to convey information (be it a story of your company, a trade offer or an announcement of the upcoming event), it should be judged according to the clarity of its message. Thus, we should always help users focus on relevant information instead of distracting them. Some of the most common examples of ignorant or malicious attempts to shift your flow include:
Intrusive pop-ups and sidebars, especially those with third-party advertisements:
ranging from nonsensical mini-windows to carousel ads, they are pure distraction. Remember the “spin to win” wheel? As quickly as it gained widespread usage, it became hated by most users. But keep in mind that a strategic pop-up—such as an exit notice—can be effective.
Floating menu bars:
a big obstacle to users with small screens.
Splash pages:
the easiest way to run a potential visitor off your site. The same goes for sign-up walls—a mandatory request to create an account before exploring the content of a website.
Hidden elements:
each element or navigation button should clearly indicate what it does (and do only that).
Social engagement elements on each page:
it’s obnoxious to constantly prompt users to visit your social media profiles.
Complicated backgrounds under text:
they make it hard or even impossible to read.