Emperors don't like Parties
Brittany awoke to the Doctor bursting into her room, a party hat on his head, slightly askew. "It's the ninth of September today," he said cheerily, a large present in his hand.
She blinked at him bleary-eyed, gathering the duvet up around her. "What?"
He looked slightly crestfallen. "Don't you know what that means?"
She just looked at him.
The present was waved in her face. "It's Flavius Honorius' birthday! Emperor of Rome! It's only right that we pay him a visit, isn't it?"
And so, ten minutes later, Brittany found herself being dragged out of the control room by her elbow, right into the midst of a marble palace. The Doctor handed her the present, and tucked his hand into his pockets, his party hat almost slipping down over his eyes.
"Now, the history," he said, glancing over at his companion. "Because you can't have a party with the emperor without the history. So, he became the emperor of Rome at age ten, rather young if you ask me, but true. It's his 22nd birthday today, so don't be too rude or anything, okay?"
Brittany choked. "Me, rude? It's you I'm worried about!"
The Doctor looked hurt. "Rude? Never! This looks like it." He pushed open a pair of double doors, crowing jubilantly at the top of his voice. "Happy birthday to the emperor!" It was then that he noticed the fifty-odd soldiers that were moving to surround him. "Oh, we'll just leave the present here, shall we?" He nodded at Brittany, and she dropped it with a loud crunch.
"Someone likes their privacy," she remarked as the Doctor grabbed her arm again.
He took a look at the guards that were almost upon them. "Do I even need to tell you to run anymore?" She shook her head. "Well then, what are you waiting for?"
They ran.
And that's why the Doctor does not normally do birthdays, roman ones in particular. Also, they make him feel old.