Solution1 - 5:47 pm on Nov 17, 2013 (gmt 0)
Ajax driven multi page lists. When you click the "Next" button to go to the next page, the (alphabetical) list doesn't get focussed at the top, as would make the most sense, but at the bottom.
When nearing the end of an article, getting some recommendation for another article shoved into my face.
European cookie law, of course, forcing me to pay attention to cookies that I really don't care about, at every new website.
Anything that moves when there is no need to, or that I as a user didn't initiate.