1x1 writer here. I'd say my biggest pet peeves are partners who don't contribute to the plot (even their characters just go along with whatever mine want to do in the IC). There's a difference between a character with a passive/submissive personality and a ragdoll. Also partners who take control of my MC without asking for permission first. It's surprising how common this is even though I don't know anyone who likes it when it happens to them. One more for good measure: Partners who post interest checks making a huge hullabaloo about not ghosting a RP with them because they hate it more than the devil himself, but then they ghost you as soon as they lose interest. The double standard is so frustrating.