Because his father abandoned him, this would mean that he's wasted his entire life chasing a dream. For example, Mao initially tries to deny that he wants to be like him and finds it worrisome that his grandfather believes he's been chasing his father. Related: New Manga Greatest Clan is Hunter X Hunter if Gon Freecss Was Evilīesides taking place in a desert wasteland where hunters harvest ice from the corpses of water beasts, the manga Desert 9 introduces more complications to Mao's relationship with his estranged father.
Mao wants to find his dad who abandoned his family to find the ninth forgotten desert. Desert 9's Mao shares the same obsession as Gon, and his father left for a similar reason as Ging. Upon finding him, Gon learns that Ging was originally motivated to get what he didn't have, which later evolved into a need to explore everything beyond the known world. Gon is driven in this endeavor both by his desire to find Ging and out of curiosity, for if being a Hunter is compelling enough to tear a man away from his family, then it has to be incredible and must be experienced. In Hunter x Hunter, Gon decides to pursue a career as a Hunter just like his dad Ging who left his family. But only one of these boys is emotionally scarred from the experience, and it's not Gon.
Hunter x Hunter and Desert 9 both tell the heartbreaking story of sons who dedicate their lives to finding their fathers who abandoned them to pursue their own dreams.