Meow.
Meow.
Meowmeowmeow!
Jack sighed. "Yes, you're cute. Now, go away."
Meow.
"I don't have anything for you. Bother somebody else."
Meow-meow.
"Stop it. Go."
Meow-purr.
"No!" Jack shouted at the little brown tabby wending its way between his legs with every step he took.
The cat looked up, startled, but it didn't run away.
"Look, fella. I'm not exactly the 'good home' sort, ok?" Jack said, crouching down. "People don't have a good lifespan around me. I don't fancy a little cat's chances. And I really don't want to lose anybody else for a long time."
The cat purred loudly and nudged Jack's hand insistently. Then it jumped up onto Jack's shoulder and began nuzzling his hair.
Jack sighed again. "All right, fine. But only until I find somebody who can give you a better home. Got it?"
15 years later, a fat brown tabby napped 10 hours a day on the desk of Captain Jack Harkness. Jack often complained that his cat was more popular than he was, and definitely got better treatment.