One irritant that really annoys me will take a bit of explaining but here goes:-

You're looking at an online newspaper (!!!!) and after reading a few things and haave scrolled down the page you come across four news item across the page. Reading from left to right I'll call them 1, 2, 3 & 4.

I see two items I want to read and click on number 2 and read it. I use the < to go back to the main page and find those items have shifted. 1 is now 4, the other item I wanted to read has disappeared and so has the original 4 and two completely different items occupy the other two spaces.

Sometimes I can get the item I wanted to read back by refreshing the page (sometimes a few times) and at other times by using "History". Soooooo, annoying.

Oh yes, while I'm on the subject of online newspapers, the ones that always have videos that start "automatically" are annoying. You have to be quick to click "Cancel" as a lot of them have absolutely nothing to do with the news item.