I would say, just see how much shit Hunter x Hunter can do in 100 episodes compared to One Piece. Maybe it's just me but every time I tried one piece the first few episodes were to painfully slow. So I tried an abridged version but it didn't have all the arcs done in order last I remember. Now both shows are different so it's not exactly apples to apples but HxH manages to make each episode good on its own, and throws in a cliffhanger like ending each time to keep you going, especially during longer sequences.

If One Piece just drops all fillers, that too is good. But One Piece also does what Fairy tail does (well, I read at least 600 chapters of one piece manga for this view) and that is having arcs where 90% isn't that important with sporadic information drops and then the big showdown. And the anime mimics that. Some detours are fine, but One Piece often feels like it's filled with detours until the important characters manage to get their asses to the final showdown. And it's why I eventually fell off the manga. I lost interest in going through so many chapters to get the meat of the arc.