Pretty much peoples opinions. I can deal with opinions well enough eventually, but at the time they happen they tend to hurt my feelings. Also, I am afraid that I will be review bombed to death.
Yeah online commenters can be harsh.
Not sure if it helps but I've only dabbled in video and artwork creation and the response has been mostly positive. Even though I suck (nothing against my ability, it's just that these are skills I barely know or use, so of course that shows in the results) - I've gotten replies to one of my ABDL artworks from someone saying that they really liked it, and no negative comments.
My YouTube videos (almost 100% low effort computer game footage - I rarely talk and only do basic, quick cut editing) are also mostly full compliments and discussions about the games, or a video is just ignored and doesn't get any hits or likes. Which is fine, I think of my YouTube channel as a kind of video based scrapbook of games I liked at one point. Occasionally someone will say something negative in the comments, or I'll have one video with mysteriously mixed up/down ratings - but it's no big deal.
If you do become very unlucky and get a huge backlash and lots of negative comments, it could end up a good thing. People might hear about it and check out your work and end up liking it. Sure, a lot more trolls will as well - but if you don't feed the trolls they'll eventually go away, while the people that like your work will stay.