The piece of shifting layout that annoys me the most in Google search results is the “People also search for” widget. It appears if you visit a search result and then hit the Back button. I usually want to click the search result below the one I just visited, but by the time I’ve moved the mouse to that search result, the Google search page has inserted the “People also search for” widget in its place.

Google Search’s addition of that dynamically-appearing widget two years ago was the primary reason I switched to DuckDuckGo.