There exists a prestigious academy with a history going back hundreds of years. Graduates are highly skilled and very much sought after for employment. For purely traditional reasons, the academy requires its students to become proficient in a skill or area of knowledge that has no use in the modern world. This could be Ancient Egyptian, an antiquated form of writing such as shorthand, knowledge of building or repairing antique steam engines, programming COBOL, etc. PCs who graduated from this academy must be sure to have this skill in their repertoire.
I was in a game with a GM that had a Masters in History, who made is a point to mention that the local peasants didn't have wheelbarrows. The rest of the players just shrugged that off but I knew that the GM was trying to tell us the peasants were on the knife edge of starvation.
All that from wheelbarrows? Yes, because before the invention of the wheelbarrow it took two men to carry that load. In it's time the wheelbarrow was the most explosive production multiplier that the peasantry could get their hands on.
This is worth two tips: One about the power of the Wheelbarrow and the other is the moral of the story...that people need to know the point you are trying to make.