As a writer I would like to avoid going down a path that has already been trampled, I would like to see new things and new experiences with different groups of characters. It bothers me that some times "plotting out" the path of a story can skew the actions of the characters in the rp to get that result. I've experienced the same in writing on my own, sometimes you look at the plot you planned out and you're like hah this will never happen.
As a player I look for people who want to include more diversity and details rather than go the same route. I like neuro-diversity, people of color, and lgbtq+ all played correctly. I personally don't think a role play reflects reality when everyone is of the same brand. And it's disappointing to hear that some people have been shunned for having characters that aren't neuro-typical.
I dislike one liners, and i cant respond to them for the life of me, but i remember what it was like back when I started. To ween myself off of the habit I put a minimum as to how much I could write before posting, and it helped me a ton to expand my capabilities.
I hate godmodding and when characters are able to do things outside of their set of capabilities. I find it unrealistic and disappointing.
I also majorly dislike it when people have one OC that they apply to every single role play. personally I feel like OCs should be as unique as the world they're being made in, and it fundamentally changes when youre jumping from role play to role play. Sure some of the characteristics can possibly be the same but how the parents grew up, how the character grew up, how the world works are just.. different.
And, as a given, I hate it when people give my character a reaction or play my character for their benefit.