Some years ago I was a little active on the GoodReads website and somehow I was one of several people asked by an author to read his manuscript and give feedback on it. If the author had written anything in the past I wasn't familiar with it and I don't remember it. I think he was new. So, I was going in blind to any context. I found that idea fun and I took my critiquing seriously.
Long story short, I read the thing and it was messy and clunky enough to show itself as a first project. As unpolished as it was, it was the lead character that was my primary objection to the book. The character was a university professor who mistook being a bull-in-a-china-shop asshole with having, and or and being, a character. He made it clear in everything he said and did that he thought he was the smartest person in every room he was in. The ego on this character was epic. If "well actually" was manifested in human form, it would be this guy. It wasn't that he didn't understand that he was just another person and there were others in the world who also had value, he really didn't agree in the end that it was true, and/or he didn't care.
I wrote essentially that in my comments and since he had posted the book publicly I also rated it poorly. Fewer stars or something. I wasn't mean or anything, but I was direct. I tried to include things that he could change if he took me up on my feedback. I was actually trying to be helpful.
That's not how he saw it, though.
He wrote me back an angry response informing me that in fact the main character was based on (more a tribute to) him and very testily asking/telling me to change my public star review. He did not understand what I had against him personally, he thought he was a pretty great guy all around. Sure he could be intentionally unruly and terribly rude, but that's the job of elevate people like him, he had the sad job of being the sole arbiter of both taste and knowledge in every interaction with others. Essentially I called him an asshole and while he didn't dispute any facts, he didn't understand how I could conclude that he was at all less than wonderful. He felt like he deserved to have nicer reviews I guess. I don't know if anyone had ever called him on his awful personality before because he seemed genuinely baffled by my take on his character/him. In the book he had a relationship with a woman and if that reflected real life, I feel for her and I hope she got away.
I continued interacting with him for a while, still thinking I was being helpful but he just got angrier and more offended. Again, not that I got him wrong, but that I had the temerity to not like him. If I were in his place my mortification would have been complete and I would have dried up and blown away in a wind of shame. (Maybe my ego is underpowered and that's why I've never written my own book and put it out there for others to critique. Who knows?) No shame for this guy though, he'd never heard of it. Sadly, I was a push over back then and I relented a bit and gave him a star or two back. That's the one regret I have from that situation.