Doctor Who: 8 Reasons The Tenth Doctor Was An Actual Monster
3. He Destroyed Harriet Jones' Life In Six Words
The newly regenerated Tenth Doctor ends the Sycorax invasion on Christmas Day and the aliens' eventually retreat. The Doctor tells Prime Minister, Harriet Jones, that Earth is noisy. He warns her that aliens know about them and they should expect more events like this. Harriet is understandably shaken and uncomfortable with this news.
When The Doctor is momentarily distracted by the arrival of his friends, Harriet's aide takes a call and tells her that "Torchwood is ready." The Prime Minister takes a moment to think before deciding to "Tell them to fire."
The Sycorax ship is destroyed, and when the Doctor realises what happened, he confronts Harriet. She tells him that she has a duty to protect the Earth and that he had even said more would come, so she did what she had to do. Ten doesn't take kindly to that and starts ranting like a psychopath.
When the conversation breaks down, their relationship is strained to its limits, and the Doctor insists he could bring down her government with six words. He marches over to her aide and whispers: "Don't you think she looks tired?"
And the rest is history. Even from his earliest moments, Ten wasn't afraid to ruin someone's life just because he disagreed with them.