Last Post: 3:23:19am, 10/05/2019
You'll just have to fast forward the flashbacks and filler-within-regular-episode parts, and skip the filler episodes. Use a filler guide. They tried to make the anime as long as possible, which ruined it. But with the flashbacks and fillers skipped it's still an enjoyable show. In Shippuden, especially near the end, some non-manga content is actually canon and worth to watch, so it's hard to figure out what to skip and what to watch.
One Piece is great, but at times can be slow. Skip flashbacks and filler-within-regular-episodes. Luckily these are more rare than in Naruto. There are a few smaller filler arcs and episodes, but they're not nearly as bad (and out of character) as Naruto's. They can be enjoyed or skipped with no problem.