The Tenth Doctor was labelled "The Man Who Regrets" by The Moment in the 50th anniversary episode, but thinking back, his regret didn't seem to show up all that often. Sure, when he reminisced of Gallifrey, the regret of what he thought he did was tangible. Compared to the Ninth Doctor, though, who seemed to have pain written all across his face, his successor was a joyous ol' chap. The Tenth Doctor seemed to regret losing his companions, Rose especially, more than losing his entire planet and race. If he was indeed the version that regrets, it's a regret that viewers didn't get to see more of it.