Bad story, incredibly number of fillers, absolutely idiotic plot and setting - it's lost halfway between semi-traditional Japanese/asian setting with magic and some kind of semi-modern setting - they used fucking modern-looking phones even in the earlier episodes, and some of the movies have rather futuristic things that don't fit in the setting.
Then there are annoying characters, who are badly dubbed (but then again, I don't think anyone would really watch Naruto in dubs, they should know better.) and ninjas that aren't at all fucking ninjas. Look, yes, it's a fictional setting, but ninja is a stealthy assassin. Wearing ORANGE JUMPSUITS and not wanting to kill people doesn't go with being a ninja. It's not stealthy, and assassins shouldn't be all that afraid of killing others. That's their job, even if they have some depressing flashbacks about it afterward.
But then again, seeing how the guy who did the manga originally wanted it to be completely different (Naruto was the main character) and not involved with ninjas at all, it's somewhat understandable why he's so out of place. The original setting was something about magical warriors transforming into animals. Which sort of turned into plot/subplot in Naruto.
Naruto would make an okay "magical warrior/superhero" but as a ninja... just no.
oh ya and it's mainstream. It's always cool to hate mainstream.