There is a reason that One Piece has managed to captivate and invest the audience for more that 2 decades and over 900 chapters. There are many things amazing with this series. Some of which I will be mentioning here.

-Story: Although the story may seem the same rinse and repeat formula of going to an island, beating up the bad guy and saving the day, the story is probably the best part of the series. There are light-hearted themes of friendship but also darker themes like slavery, discrimination and fascism. It manages to be funny, sad and outright depressing at sometimes which I really like.

-Characters: The characters are mostly amazing. You'll get one or two lazily written characters here and there but most are extremely well written with amazing design and backstory.

-Art: I feel the art in this series is pretty amazing and helps to bring this fantastical story to life.

-World building and mysteries: But at the end, I feel like the reason OP has captivated me all these years is its fantastic world building and mysteries. The world feels alive and we feel and see the world is changing to each and every action of the characters. No island is similar to another and the writer does an amazing job to immerse us to the world. The next thing is mysteries. There are so many mysteries that keep me invested to see how they turn out. The writer is extremely proficient at giving us hints and foreshadowing which makes rereading this series as much enjoyable.

Overall, I feel like it is an amazing series to read if you're new to manga. The only negative aspect to this series is that it is long and can seem intimidating to get into but once you start reading, it starts feeling short.

10/10.