The main character is really well written. He suffers from an incredible amount of clinical depression, which wasn't magically cured when he reincarnated into another world. This is legitimately one of the best depictions of actual realistic depression I've ever seen in media, especially manga. As someone who deals with similar issues, it's actually really relatable. I don't agree with everything he does, he's a real piece of shit at times, but that's the point. Depression and anxiety disorders can and WILL warp your perspective, which makes it really easy to act like a piece of shit. But he doesn't just wallow in it either, he actively tries his best to keep moving forward, helping people, and trying to grow. He forgives people who wrong him, he realizes when he's been an asshole and tries to make up for it, and tries to change. In fact, he's changed DRASTICALLY from the start of the story to the current point. His character growth has been amazing to watch. That's some of the best parts of this series, that's what really drew me in.