Idea by @minipage

Use the word "flibbertigibbet"

minipage

As a sociopath, flibbertigibbets were Sherlock Holmes' least favorite people.

Their incessant need to talk about details, problems, and issues that don't really matter.

Some things matter.

Your personal problems do not. 

At least, not to him.

Think global.

Think big.

Think about long term.

Five year olds are a good example of flibbertigibbets.

He was quite certain the word was invented by someone in that age range.

Yet, of the four people Sherlock Holmes truly loved in this world, a five year old, and a notable flibbertigibbet was one of them.

Which was very frustrating but little Sebastian had him wrapped around his thumb, which he insists on sucking on.

It was a rainy day that found Sebastian and Sherlock stuck inside the latter's apartment with nothing to do besides stare at one another.

And talk.

Sebastian talked a lot.

It was impossible to think when a five year old was running around, jumping on the furniture (that didn't bother him).

"I'm hungry," Sebastian declared, not even an hour after arriving.

"I'm not," Sherlock said.

"Unkie," he whined.

"You can't make your own food?"

"Can't you make food?"

"Well—- no."

"McDonald's!"

"Absolutely not," Sherlock said. "Do you know how that food is made?"

"Magic," Sebastian said, picking up a letter opener and looking at it with curiousity.

"No. That's very wrong, Sebastian."

"Unkie, I'm still very hungry," he said, dropping the letter opener on the floor. He moved on to the rest of the discarded items on the desk.

"There's crackers in the pantry," Sherlock said.

"I still want McDonald's."

A part of Sherlock wanted to strangle the child, just to get a moment of quiet.

"We're not going to McDonald's," Sherlock said. "It's raining."

"Are you afraid of rain, Unkie?" Sebastian asked, climbing onto the desk chair to get a better view of the tiny world of the apartment.

"No," Sherlock said. "But your mother forgot your raincoat."

"I could borrow your coat!" 

The child's talking finally got to Sherlock.

"Yes, you may borrow my coat, Sebastian," Sherlock said, standing up. He was giving into the child. "Go grab it and we will go to McDonald's."

The child stumbled off of the chair.

"That's why I like you, Unkie."

It was such an adult thing to say that it made Sherlock smile.

Sebastian ran for the coat rack, pulling for his uncle's familar coat. The entire coat rack fell as the coat came free, landing with a clatter beside Sebastian.

"Whoops," the little boy said. 

"Leave the mess," Sherlock said.

"Mum makes me clean up my messes," Sebastian said, opening the door and heading downstairs.

"Well, your mother isn't here, is she?" Sherlock retorted as he shut the door.

"Mum doesn't let me have McDonald's," Sebastian said when they reached the first floor. "She says it's unhealthy."

"It's very unhealthy," Sherlock said, pushing the front door open.

Ten minutes later, they were sitting in the McDonald's closest to the apartment. Sebastian's little legs swung back and forth as he regaled Sherlock with kindergarten gossip.

"Well, Juliet is obviously not very bright," Sherlock said.

"Yes, but I love her, Unkie."

"You think she's cute," Sherlock said. "There is a difference."

"She's very cute." He stuffed a chicken nugget in his mouth.

"We're going to get married," Sebastian added, mouth full of "chicken."

"I calculate the odds of that to be close to 0.0456%," Sherlock said.

"That's good right?" Sebastian's eye lit up and he actually swallowed his food.

The boy's enthusiasm for a world he didn't know touched Sherlock.

"Yes," Sherlock said. "That is very good."

Sebastian went back to eating and talking.

Sherlock didn't mind.

I'm sorry for turning this into another fanfic. Oh, wait. I'm not. Ha! All characters belong to the Sir Arthur Conan Doyle Estate.