protagonist of Hunter x Hunter Gon Freecss's father, Ging, inspired him to take up hunting. At the age of twelve, Gon left Whale Island for the hunter test with the hopes of finding Ging, speaking with him, and maybe seeing his father for the first time in his memory. Gon spent a lot of his life pursuing Ging despite being raised by a very caring aunt and great-grandmother, with little success.
Gon's desire to meet Ging and please him consumed him for a long time. Even after passing the hunter exam and receiving his hunter's license, Ging had no desire to be a part of Gon's life. Ging never sought out his son or showed him affection, despite encouraging him to pursue a dangerous lifestyle and putting Gon's life at risk second-handedly.
Ging initially made the right choice.
While Ging did abandon Gon, he left him in excellent care. Ging was only twenty when he had his son, and the identity of Gon's mother is unknown, so he took on a parental role on his own at a very young age. Eventually, he wanted to pursue his own self-fulfillment and explore the dark continent, something he couldn't do with a son. So, when he was two, Ging left Gon in the care of Mito Freecss, his cousin, and Abe Freecss, his grandmother.
These two are seen to be very supportive and kind, raising the young boy to their best ability and making sure he is loved. This was the decision that made the most sense for Ging, while also being beneficial for Gon. He recognized that he wouldn't be able to take care of Gon himself, so left him with people he knew would give his child the best quality of life possible.
Ging Was Unable to Completely Break Ties
Ging's biggest flaw wasn't leaving Gon, it was his inability to let go of his family completely, which in turn left Gon feeling unfulfilled. He knew that he wanted to embark on his own journey and wanted nothing to do with his son, yet the hunter always gave him enough just insight into his life to keep Gon interested. Ging encouraged Gon to take the hunter exam and get his license, and Gon did exactly that just to impress his fathering hopes of making him proud. Though, when the time came for him to show his son some affection, he was flustered by simple conversation.
Throughout Gon's journey to find his father, he faced multiple life-threatening trials and tribulations, all orchestrated by Ging. The young boy risked his life on countless occasions, all to prove something to a father with no interest in him whatsoever. Even to earn a heart-to-heart with his dad, Gon had to climb the world tree, which is so tall it has the potential to surpass the atmosphere. Time and time again, Ging's attempt at encouragement was poor at best, forcing his son to pursue lethal battles, trials, and adventures when he knew he wanted nothing to do with him.
After leading Gon on throughout the anime, Ging decided that for him to be a part of his life his son had to prove his worth and earn this, showing his father he's worthy of his time. Giving Gon up was not Ging's greatest failure as a father, it was his persistent need to be in Gon's life when he didn't want him in his.