You know what fantasy stories don't use enough? Different measuring scales, and confusion caused by them. Because before the metric system, practically every place and culture had their own measures for weights, lengths and distances. It would be fun to add that into a story for added realistic cultural confusion.
The average dwarf is four or five feet tall, but not in human measures. Yeah they're still shorter than humans but the dwarf foot (and the namesake measure of length) is bigger in proportion to their body. "Is that in dwarf feet or human feet?" is a common question to hear on construction sites, wherever human carpenters and dwarf masons are working together.
A dedicated local Common Misconception Historian has a pet peeve about the whole "princess Featherblade was only 12 years old when she led the attack on Marshland Halls" -myth, because the historical recordings on the human side are off. While she was remarkably young, that myth came about back in the day when humans were still trying to apply "dog years" to elves, and in an elven life span, 120 years is not a direct equivalent to a 12-year-old human.
A whole culture whose smallest unit of weight loosely translates to "about as much as an apple", and varies from region to region depending on the size of local apples. These people are famed for their alchemists, whose uncanny ability to simply measure their ingredients by heart, making their recipes essentially impossible to replicate. This famed skill is a matter of survivor bias - the ones that don't have that knack ten to explode into fine mist.
