Flaws and imperfections. This is mostly the reason why I rarely gravitate towards the main protagonist and a lot of the villains in fiction. A lot of them just don't have any flaws. They don't have those issues and they aren't polarizing. For me that's not very relatable. You can be toughest, most badass guy out there... If there isn't anything underneath that, I'm out.
And flaws/imperfections go beyond "weird/annoying" tendencies. Like, if a character tends to have a scratchy voice, that isn't a good imperfection for me. Not deep enough or enjoyable enough for me.
And imperfection is Naruto's rhetoric and way of saving Sausage. That's a mentality that can be viewed as harmful. Watching a character go beyond shackles that would be questionable to some is infinitely more interesting than "Watch me kick ass". Even if they don't succeed, the journey is always fun both in the series and within the fandom.
I like flawed people, what can I say?
edit: I'll also add this. I don't like Sasuke. I find most of his character traits and plot points annoying and rather distasteful... But that's a flaw. There are crucial issues with his character that even I can appreciate. Flaws that are not there because of lazy writing, but rather designed imperfections from the creator.
That's why whenever I rate Sausage I always drop that 7 or 8/10 (unless I'm trolling or pissed for some reason) even though I vehemently despise what he stands for, his addition and mark to the story is permanent and unavoidable. I can respect that quite a bit.
Yeah, a character that I despise I put higher than a character like Goku or Luffy. Legit.