Wow... this is a hard question. I love everything about it. From discovering my characters and their problems, to interacting with my readers. It's truly my dream job. I guess the best part would be coming out of my shell and being able to talk to people (I'm very introvert and shy).
I have an awesome street team on Facebook at https://www.facebook.com/groups/16360... It's a blast talking to the members there and they have become my main support in asking for opinions on cover art, plots, and getting beta reader feedback. It's fantastic to have them!