One, two! One, two! And through and through
The vorpal blade went sincker-snack!
He left it dead, and with its head
He went galumphing back
One of the most important rules of deduction is to never let someone else's perspective be forced upon your own. Always form your own opinion based on the facts. If the facts say that the dead man had several homosexual lovers but had a happy family life (wife, 2.5 children etc.), and neither knew about the other, then it was likely that the wife wasn't the killer. Of course if the facts also said that the dead man had frequented gay bars and one of his children happened to also be gay, then the facts helped produce a motive for one of his children to kill their father out of anger, because they saw him, the father, cheat on their mother.
The facts will then say that this is not a clear enough motive. That if the child in question (early twenties, trying to find out their sexual identity through experimentation) did find their father cheating then they would tell their mother what they saw. The two lives have now met, offering up the wife's motive to kill her husband on a silver platter. It doesn't hurt that the food on that silver platter was laced with poison.
Now imagine if you were deducing all of this, when suddenly someone made a comment about the pair having an open marriage, or there was a cook or a maid involved somehow. Now you have to look at your clues with a whole new set of eyes, from a whole new perspective. This is why Sherlock hated it when people talked to him while he was deducing. It was also why he liked to have all the information that he could at hand.
When all is said and done, and we find out that the cook is really the killer, all the pieces of the puzzle finally become clear. The cook was blackmailing the man by threatening to tell his wife about his illicit affairs with those members of the same sex, but when one of his children found out about the man's affairs, they quickly called their mother and told the man's deep secret. The wife, of course had picked up on this by simply knowing her husband and was happy to have an open marriage because while they both loved each other and wanted to stay married, he wasn't sexually attracted to her. When poor Cook found out about this, and that her high paychecks were coming to an end, she couldn't believe her horrid luck and decided to kill her boss, because then during the grieving period she would at least still have a job. It would also give her a chance to look over handy work. Unfortunately for her, Sherlock knew the three most common types of crimes were: crimes of passion (love, anger, hate, jealousy), crimes for money, and crimes of opportunity.
Sherlock was one of the few people in the world that could tell which was which. This made him very dangerous to certain people. Kidnapping John wasn't just a crime of opportunity, it was a crime of passion. Jealousy reared its ugly head into poor Moriarty's heart. It nearly consumed him, leaving barely enough of the man to devise a plan, a plan to get our dear Sherlock to notice our other consultant. Now you might think there's a little bit more work you would have to put into it, especially when you already have a boyfriend (looking at you Moriarty you have Moran what are you doing with Sherlock), but when you have an all access pass to someone's mind and you're living rent free in there, the rewards tend to be spectacular.
For instance you could get a certain detective (maybe consulting, maybe not), to reveal his feelings for another person. Sexual or romantic or not, either way, you just got someone, who loves giving emotions the cold shoulder, to admit he has them.
You also get someone, or some people to admit they care about him. Maybe it's in a familial way; maybe it's his big brother off to help him. Maybe it's the DI who has become, not only an important friend to the man, but almost a father figure. You also get people, who usually heckle the poor consulting detective, to help him. They also start to treat him as an equal because let's face it, uniting people against a common enemy is one of the best ways to humanize each other.
Now poor John Watson though. Suffering the curse of the wolf, all alone listening to shitty kid's music, he has no one with him. But with this little, let's say experiment, he does have people who care about him. People who are willing to put aside their differences with others to help save him, people who are willing to save him. People who are willing, and happy, to have people confront their own emotions to help others confront theirs.
They say sentiment and emotions aren't helpful in certain lines of work. Not when you're a surgeon. Not when you're a social worker. You have to keep yourself at arm's length, keep your emotions in check, and make it known to yourself that shit's going to happen that you can't control.
Sentiment and emotions are helpful in other lines of work. Like when you're an artist and you must put your emotions on a canvas or the pages of a word file (or an actual notebook), or in a movie or a play. It's the job of an artist to put things that are hard to understand or hard to say into simple and easy ways for the rest of the populace to understand. Emotions and sentiment are also good if you're a cook/chef. You must be passionate for people to see how truly talented you are with your culinary skills. Nothing short of passion for what you make will ever have your food taste the way it tastes when you enjoy it truly for the sole reason for cooking.
But nothing compares to the sentiment that is a friendship of course. Friendships are the most amazing form of sentiment. What's the truest way to tell if someone is your friend you ask? Ask yourself what would they do for me? What have they done for me?
In Sherlock's case, John had killed a man, and given Sherlock something his massive intellect had never been able to give him. A friend. John had also saved his life. And with one look they both decided to die with each other in order to escape a mad man. While happily they didn't die and the mad man escaped they managed to have many more adventures together.
In John's case, Sherlock had also saved his life, in more ways than one. Before Sherlock nothing happened to him, he had nothing to put on his blog. He would have nothing even remotely interesting about himself. Who cares about an Ex-Army Doctor with PSTD and psychosomatic limp and a wounded shoulder? But Sherlock did an amazing job bringing back John from the brink of despair, from the emptiness and loneliness and a boring civilian life. It was Sherlock who showed John the reporter in pink; and it was Sherlock who made John's life exciting again, filled with danger and explosions and fire and everything you could possibly imagine, all because of a silly man with a made up job.
Sure John had all the aspects of a civilian life, and sure Sherlock brought danger and excitement to their lives. But nothing compared to the times when they didn't have a case. Sherlock was just as bored as John, only John had ways to occupy himself that didn't involve setting things on fire or blowing things up in a microwave. Sherlock was all for stimulation, that's why he didn't get high anymore. It's also why he blew things up in the microwave and set fire to things ("our little pyro" as Ms. Hudson would say teasingly when Sherlock would manage to start a kitchen fire, but then expertly put it out in a few seconds – as long as it wasn't a big fire). And while it did annoy the hell out of Ms. Hudson when Sherlock did inane things while waiting for a case, like shooting at walls (something she liked to remind him of), or blowing things up, or even at one point being so bored he bought a tank of helium and some balloons and blew them all up in order to annoy everybody. And when he ran out of balloons he and John and Ms. Hudson all inhaled some helium and talked for hours trying to make the each other laugh.
Life was a pleasant mixture of dullness and excitement. It was a pleasant mixture of danger and peace. But it wasn't something that Moriarty could play with. The well-thought-out crime was more of way to admit feelings, and also to annoy people. Moriarty was like a really bad version of the Joker.
~.~
When they walked into the library they expected so much more. More surprises, more danger, and the worst of them all, more poetry! They looked around building, Sherlock texting Lestrade and his team because he wanted, for one of the few times in his life, to follow the rules of his plan.
"Sherlock," James Moriarty said over the intercom. "Come and find me!"
"Where do you think he is?" Sherlock asked Mycroft.
"Dr. Watson or Moriarty?" Mycroft asked.
"Either or, whichever one," Sherlock answered vaguely.
"That helps so much," Mycroft replied sarcastically.
"I'd say don't let the door flatten your ass on your way out, but you sit down all the time and your ass has flattened all by itself," Sherlock remarked, a bit rudely. His words were harsh due to his lack of patience with the task at hand. They only had 15 hours left. Sherlock was starting to get anxious. What if there was another god-awful poem that led to somewhere else.
"You really need to get a better attitude. Maybe some exercise will help. Might I suggest yoga? Might help clear your mind."
"You suck. Go leave me be and eat some cake," Sherlock told his brother, rolling his eyes. "Or why don't you just pig out on some other pastry. Leave me be."
"Let's just get your problems off my desk. I have bigger and more important problems at hand. I have an election in Spain, a small economic crisis in Greece, and, not to mention, I have to help run this country so the faster you're out of my hair the better," Mycroft replied angrily. "Stop your whining and think about someone else for a change you selfish bastard."
"I am! Why do you think I'm here? Why do you think you're here? Because I care for John Watson! He's my best friend, I can't lose him."
"Oh Sherlock-" Mycroft started.
"No, enough. I don't want to talk about it," Sherlock said putting his hand up in front of Mycroft's face, "Not now, not here. I'm not talking about it."
"Then when, Sherlock? When are you going to open up?" Mycroft asked his voice soft.
"I'll have to check my schedule, but I think I have an opening the first Monday of Never," Sherlock said. "Now can we get back to the task at hand? Please?"
"Only because you won't let it go," Mycroft said.
"A man's life is in danger!" Sherlock said, shocked at Mycroft's apathy.
"A man's life is always in danger. Just because you know him doesn't make it any different. If my life was in danger would you even try this hard to save me?" Mycroft asked.
"Of course I would make you stop eating cake. I'm not a complete monster!" Sherlock said sarcastically.
"Hardy har har. You should be a comedian."
"I would, but well, you know, I can't stand people. Or drawing attention to myself."
Mycroft cocked his eyebrow. "Right."
In response Sherlock just snorted. "Come on let's get going. We don't have much time."
They both stalked across the library, looking carefully around corners, opening doors and keeping their senses heightened ready to expect the unexpected.
And that's when they heard Moriarty's voice.