I'm not completely terrible at it, but I wish I was better at comedy because I definitely feel a bit weak at it. I also wish I was better at horror, but I'm generally weak at it as well. I'm also super weak at writing anything that's "normal", like no supernatural, fantastical, science-fiction-y, etc. type elements in it. I generally can only do the occasional one-shot that's like that, and like I kinda wish I was better at it, but at the same time I've also accepted that writing weird shit is just what I do and part of who I am so yeah.
I also wish I were better at descriptions. I'm not terrible at them, but it probably shows in my writing that I favor dialogue and like introspection into characters' thoughts and stuff like that over physical descriptions of anything at all.
Also, I wish I could write poetry besides haiku at all well.
I mean, at least I'm decent at haiku, which is my favorite, but I'd love to be able to write other forms of poetry without generally sucking at it.
Oh, and story summaries.
Ugh. I'm so bad at them, and I wish so much I could be good at them!