Part 1 had that captivating introduction to the world of Naruto, most of the introduced characters were genuinely developed and the plot was interesting, there were still all these mysteries (e.g. the nature/origin of the 9 tails, akatsuki etc) etc, in short it was fantastical and the story had incredible potential. In part 2, it simply started to lose all of this, already established characters were ignored while newly introduced characters were half-assed wrt development generally killed off in the same arc as they were properly developed, the main characters Naruto and Sasuke gained no new dimension to their character (Sakura never had one to begin with); the new themes contradict the old ones (the child of prophecy bs vs the there is no destiny), asspulls everywhere and in general, it started getting repetitive.
This manga went to downhill in part 2 imo (only the pain arc and possibly this 1 were the only decent arcs of part 2), only reason Im keeeping up with it is to finish it after having kept up with it since childhood.