What is your favorite anime and why?

My favorite anime is One Piece. I like how the characters were each given their backstory showing their childhood experiences that made them who they are. I also like how they incorporated real world issues like war and social class. I also like that they don't spend a bunch of episodes on them training since we can assume they do so on the ship between arcs. Plus, the adventures are cool, especially the epic entrances Luffy always makes.