very interesting plot for me, and naruto seems to keep feeding you titbits of information so you keep caring about the main mysteries, which is a problem i've found with other manga who give you loads of action but the main object is so far off in the distance it's almost forgotten.
the characters are really relatable and deep as well, in particular I find the theme of characters like Naruto, Sasuke, Hinata, Chouji, Kisame etc of trying to find their place inthe world very relatable. as well as characters like Orochimaru, Jiraiya, and Nagato's quest for the truth and or peace.
and there are many interesting political themes underlying the manga- Naruto's history is so full and rich it's almost if not more interesting than the current timeline imo. the machinations between oro, danzou, hanzou, nagato, madara, tobi etc are really intriguing.