I hate when you can tell your partner didn't read your post.
If I have a character approach their character, holding a tray of food asking to sit down and join them. It seems soooo obvious that they would put in their reply that my character sat down and their character mentions they should eat. Like fuck man, my character has food. Get your character food but don't backtrack because you can't read a simple sentence.
Or even if you're brainstorming with a potential partner and you ask a simple question and they don't answer it so you have another back-and-forth with trying to figure out a certain concern. I can understand it happening once, like maybe they accidentally forgot to answer it in a PM but if I have to ask the same question three times then I get the feeling this person doesn't know how to read or only picks out information they care about.
All in all, I just dislike absentminded folks who don't read, whether it's when discussing a RP or making an actual post. It's like some people are so self-centered or oblivious that they only care about their own character. I mean you can usually tell when someone has glossed over your post and just spit out whatever they felt like. I'm just asking for consideration. But seeing inconsistencies in posts because people aren't more aware, just breaks my heart.