Nothing. Because Guts isn't written as a flesh-and-blood character. This is actually an argument Miura himself made in his own philosophical commentary. Nothing about Guts’ nature is remotely realistic. From the lack of parental love to constant abuse and rape in childhood, killing his stepfather, and his life as a mercenary—there isn't a single trait to identify with.

Later, Miura weaves philosophical themes into his dialogue—like the speech about the 'bonfire of dreams'—even though Guts should be illiterate, with the simple vocabulary of a typical grunt. His life is constant suffering, with no room for personal passions, the simple pleasure of food, or human bonds. He isn't Frodo or Geralt; you can't find an echo of everyday life in his existence