Even Sasuke is innocent here. To quote him in the Kage Summit Arc, "What the f*** is wrong with you?!" He didn't want Naruto to obsess over him. Naruto just did it against the wishes of EVERYONE else.
Yes that was where naruto's character started to take a dive, also if ay stayed in that mind and did go after sasuke he would be better but no cause naruto cries like a (as Freeza abridged calls vegeta) a little kitten and he stops hunting the guy that attacked his brother.
And, again, this is why I loved that bit with Ay taking Naruto's pathetic begging, throwing it back in his face, calling him a weak little b****, telling him to grow up and that this is the reality of things.
And Sasuke even tried to beat that into Naruto at the end of part one, hence the "How could you possibly understand?! I have lost everything! You never had anything to begin with!" line.
Naruto kept thinking that just because they were "alone" as kids (regardless of circumstances), that somehow made them "the same" on every level. This only further shows how Naruto doesn't truly know or understand anything about anyone unless they're much more similar to himself and yet we're expected to believe he's SO empathetic.
I actually agree with sasuke at the end of the kage summit on naruto needed to stop.
You know here is something I've been thinking about for a long time, and it's the topic of nostalgia. As far as I can remember I've seen tons an tons of people defend the Naruto series even when it comes to it's flaws especially the major a ss pools ya'll know what I'm referring to, and the ending especially because of Nostalgia....
Now here is the thing Nostalgia is a period or place of reminiscing fond memories. That by itself is very subjective.
I don't think Nostalgia alone is enough to justify the quality of the series because Bleach to me I've got great memories of, but I don't use the Nostaglia of Bleach to justify it as an amazing series cause I know that yeah the series was great at this point, and could've been perfect before the quality went down.
A series should be judged from a critical perspective not through the needs of nostalgia cause that just blinds you. The same thing can be said about Naruto, I've got great memories of Naruto more so from Part 1, then Part 2, but that doesn't decide my factor of the series being amazing. It just means the series was great here, and then it just went down.
I mean lets face it most people will agree that Naruto Part 1 was amazing from start to finish. I agree with that too to an extent, but look at this way that's 244 chapters out of 700. after that you've got loop of occasional goods, and a lot of what the hell is that? That's the rest of the 456 chapters.
Last i check 244 chapters of Part 1 is 35% of the series
The final 65% of the series is Part 2.
Most of the problems the Naruto series has stems from Part 2 more so then Part 1, and once again that's 65% of the series that is saying something. I mean you guys know I really like the first half of Part 2, but I won't pretend like the problems are there cause they stick out especially after Pain.
You know what though, just on the topic of Nostalgia I'm gonna just share this.

Ok I've said this before and I'll say it again just cause somethings nostalgia doesn't mean it's going to be great later on its why the Nostaglia critic exists.