Isn't the complete monster people keep labeling him?
On other forum people keep obsessing on the whole killed 56 infants schtick (Even though there's proof he was in Root during time in which inhumanity is all over the place).
Plus his crying before fighting Hiruzen Sarutobi, then during war arc Sasuke confronts him on his reason for attacking Konoha which he says he doesn't believe he did it on a "whim" and Oro goes silent. Lastly, there's him sulking in front of his old mentor.
To top and confirm most of this there's even Tsunade saying "he's changed somewhat.."