Inspired by the deleted scene on the Doctor Who Series 3 DVD set. If you haven't seen it… OMG! It's hysterical!
Don't Let Me Eat Pears
As the Doctor and Martha stepped into the TARDIS, the Doctor couldn't help but grimace slightly. Something was very odd. His tongue felt strange, like there was a nasty aftertaste lingering there. As he walked over to the console, the aftertaste slowly became a definite taste that he didn't like… and that he recognized too well.
He turned to Martha with a glare. "Number five," he told her firmly, clearly upset.
Martha looked at him with surprise, stunned by the Doctor's attitude. "What?"
"Number five," the Doctor repeated, taking a step towards her. Seeing that she still didn't understand what he was talking about he huffed. "The twenty-three instructions that I gave you to follow when I was human."
"What about them?"
"Number five was don't let me eat pears!" he exclaimed.
Martha watched his expression for a long moment. Suddenly, realization flashed in her eyes. "Oh, my gawd! Did you eat a pear?" She quickly went to his side and started to examine him. "How do you feel? Any sign of swelling, headache, fever, nausea…"
The Doctor pulled her hands from his neck, where she was trying to check for swelling. "I'm not allergic to them," he interrupted bluntly. "I just hate pears! Why did you let me eat pears?"
Martha rolled her eyes but sighed slightly with relief. Here her dearest friend had panicked her into thinking that he was having some kind of horrible reaction when he was just being a child. "I was a little busy," she pointed out. She gave him a hard look. "Being a housemaid, if you recall. Besides, you just said you aren't allergic to them so what's the big deal?"
"The big deal is that I have very sensitive taste buds!" he emphasized, putting his hands into his trouser pockets. "Now I'm going to be tasting pears for at least a month! If I'm lucking! I mean, after I tasted mistletoe oil, I tasted it for three weeks. Mistletoe oil isn't bad. But pears! I hate pears!"
She blinked at him for a moment before giving him a knowing smile. "If you hate them so much, why didn't you instruct the TARDIS to make that part of John Smith's personality?"
The Doctor stared at her for a long moment before quickly turning and going to the console, not answering her question. "Right. Where to now?"
Martha chuckled slightly under her breath. Okay, so she was probably going to have to listen to the Doctor complaining about hating the taste of pears in his mouth for a while. It could be worse, in her opinion.
He could have onion breath for a month.