One Piece is a long-running shonen anime that has been on the air since 1999 and has amassed a huge fan base over the years. One Piece has become a cultural phenomenon for its compelling story, unique characters, immersive world-building, humor, and thematic depth. While it may not be everyone's cup of tea, it has earned a place in the hearts of many anime fans worldwide. 

2. Full Metal Alchemist

The series follows two brothers, Edward and Alphonse Elric, who use alchemy to try to bring their deceased mother back to life. The attempt fails and costs Edward an arm and a leg, while Alphonse loses his entire body. They begin a journey to find the Philosopher's Stone to restore their bodies and uncover a conspiracy involving the government and the military.

3. Hunter x Hunter

Hunter x Hunter is a popular shonen anime that has gained a significant following over the years. The series follows a young boy named Gon Freecss as he sets out to become a hunter, a special kind of warrior who travels the world to find rare treasures, uncover hidden secrets, and face dangerous foes. Hunter x Hunter is a great anime series because of its engaging storyline, unique characters, complex world-building, intelligent writing, and exploration of dark themes. It appeals to a wide range of audiences, from casual viewers to hardcore anime fans, and it has earned a well-deserved reputation as one of the best anime series of all time. 

Overall, these three anime series hold a special place in my heart for their unforgettable characters, gripping storylines, and incredible music. If you're a fan of anime or just looking for a new show to watch, I highly recommend checking out "One Piece", "Hunter x Hunter", and "FullMetal Alchemist".