I just watched a Soviet Union rendition of Sherlock Holmes. Shockingly good. You simultaneously get the feeling that you're experiencing genuine Russian culture and Victorian Britain at the same time.
Like many kids, Sherlock Holmes always grabbed me and captivated me. The winding-area on this watch is scuffed up; the previous owner was probably regularly drinking too much and winding it when hungover. Amazing.
And profitable, too, if you can apply it in business.
The easiest Holmesian deduction is looking for the origination of a thought.
So let's you meet someone at a party and they say, "You know, I believe in doing business fair and square... never cheating anyone."
Then, start thinking,
"What the heck made them originate that thought?"
Someone whom it never crossed their mind to cheat in a business deal doesn't say that. That means that either (1) they were cheated recently in a business deal, or (2) they regularly cheat people in business deals.
Possibly (1), but more likely (2).
This is close to a superpower, and a a shockingly accurate predictor of human behavior. People who say early after meeting them they want tranquility, that they believe in fairness, or that they dislike conflict -- very often lead un-tranquil, un-fair, high-conflict lives. Why else would they thinking about it?