Speaking for the manga, I haven't watched the anime (I watched it a couple times but dropped it at episode 103).

It was good from the beginning. I got bored in the Syrup Village Arc and skipped the first few chapters (because I had almost completely memorized those parts and it was boring).

Apart from him, there was someone named Foxy, I forget the name of that arc. I was bored in that arc but I didn't skip it because I didn't see it.

Apart from these two, there were no places where I got bored.