Yes, there are three reasons why i don't like One Piece.
1. It doesn't have a great stroy such a Naruto.
2. Most of the shows is about them such having fun and maybe if you are lucky you get to see a fight after 30 or episodes.
3. Most of the characters aren't really entertaining except maybe for Zoro and Ace.
One Piece Storyline:
It has a better story line. A kid that wants to become the King of the Pirates, find a great treasure and be known to all across all seas and lands.
Naruto storyline:
A young kid wants to become the leader of a village.
Thats rich saying One Piece is all about having fun, when you look at Naruto series, all the kid is doing is chasing a friend, loving someone who doesn't like him and paints all over stone faces.
Zoro and Sanji have almost the same personality except Zoro loves swords, Sanji loves women. I don't see how you don't find them all entertaining. Maybe it's just you prefer watching something with a less meaningful story line that involves, flashbacks, crying and fillers in abundance.

That's my opinion.
Forgot to add, the first episode of Naruto didn't show any fighting. Just two guys running around in the forest chasing a kid. First ep of One Piece, Luffy owns a entire pirate crew.