The Tenth Doctor generally displays a light-hearted, talkative, easy-going, witty and cheeky manner, but repeatedly demonstrates a vengeful and unforgiving streak as well. His strong personal sense of justice makes him quick to anger when he feels it is violated. This is coupled, however, with an intense sense of regret of the deaths of both his friends and enemies.
The Tenth Doctor has a tendency to babble, mixing apparent nonsense with vital information, sometimes acting erratically to put his enemies off guard. He is prone to making comments that to outsiders seem obtuse or rude, sometimes to his own embarrassment. He is also able to rapidly switch between moods, from mania to anger to nonchalance and uses this as a form of reverse psychology on several occasions.
The Tenth Doctor is more extroverted and gregarious then his predecessor, quickly establishing a firmer rapport, is openly fond of mankind and is apparently in awe of their tenacity and curiosity, a trait previously exhibited by his fourth incarnation. However, he is also quick to criticise mankind when he feels it is necessary. Indeed, his confidence in the human race becomes far less pronounced as time goes on.
The Tenth Doctor sometimes dons a pair of spectacles and suffers from loneliness. He uses his sonic screwdriver quite often, relying heavily on the device. Much as the Ninth Doctor frequently declared things "Fantastic!", this Doctor has also favoured certain phrases on various occasions such as "What!?", "I'm sorry, I'm so sorry", and the French expression "Allons-y". Like his predecessor, the Tenth Doctor shows a fondness for human popular culture—a characteristic not all of his previous incarnations seemed to share—but even more so, to the point where he finds himself unknowingly quoting the song "Circle of Life" from Disney's The Lion King during a confrontation with the Sycorax leader.