By far,
The Orphans of Hidden Rain: They not only lost their families, but they also had to endure and survive to the 3rd great ninja war.... Since the place they lived in, became the battlefield....... Shinobis that would find them, would kill them, as suggested by orochimaru when he met yahiko, konan and Nagato.
Naruto lost his parents and was seen bad in his childhood
Sasuke lost his parents and was traumatized.
But again....
This orphans got their parents killed, were not seen bad, but rather they would KILL THEM instead+ I guess they starved alot, which is a thing that neither Naruto or Sasuke passed through, and add over that the emotional feeling of seeing the place you could call "home" being torn into pieces.
This comment is made in honor to: Yahiko, Konan, Nagato and the other Orphans from the third great ninja war.