What part of writing do you absolutely hate? Are we talking editing? Researching? Revisions? Or is it something else?
I use to not be a fan of research but now I absolutely love it. I use to not be a fan of revising. But now I do enjoy that as well.
The thing I hate the most is editing. When it comes to commas, past tense, effect vs affect, which is something I can’t seem to remember, dangling participles and gosh so much more. I have on many occasion dub myself the Queen of commas and past tense in the sense I am so bad at them I rule.
I know or rather I feel I can’t possible be alone. Yes, there are those who love to edit and do line by line editing. I do tend to give them a, “What the heck is wrong with you?, look. How can any possible enjoy doing that? But there are. Thankfully there are.
I have editors for a reason. They can do the stuff like this that I can’t be bother with or don’t want to be bother with.
I give all the props to editors. It is not easy and very time consuming. And as Mark Twain put it, “Find a job you enjoy doing, and you will never have to work a day in your life.”
So, I will leave it to them. I will go back to the job I love doing which is writing.
Sharon C. Williams-Author 
I hate trying to market my books. I never know if what I’m doing is making any difference or not and I usually spend more on ads than I take in. It’s challenging because I’m both indie and traditionally published so really can only change the price on one book.
Oh, dear gosh how did I forget marekting. I could not agree with you more. I am also a hybrid author, Laurie so understand what you are saying. It takes so much time and effort to market oneself even when one’s publisher does help with marketing. One just never knows how effective one is being.