I dislike that it's only on Digital Teletext now, which gets rid of Davord, forces lines to be short (hence often ruining poem structure) and makes us watch Goldenballs.
I also dislike people who write in insisting they're not human (as That Thing cited, The Barking Tree is an example), and try-hard 'random' clichés. These groups often overlap.
Regarding the former, WLW's giraffe persona annoyed me back in the Jaffa Cake age but he has improved a lot. Also, those who write in as a character (Flyte or The Brigadier, for example) aren't necessarily part of this rule. I know that these two groups may seem synonymous but I definitely know the difference.
I don't like people posting replies to earlier letters often as I don't consider it a discussion forum, especially when they're just cheap insults. I work my insults into proper letters
I don't like most newbies but believe they should be given a chance. Hence, (though this is seemingly contradictory) I don't like that there aren't many newbies.
I don't like stolen punchlines.