From publisher blurb:
Humans Are Weird is chock full ideas for making humans stand out from other beings in your setting, letting you avoid both well-worn tropes like "Humans are average at everything" or "Humans are, um, adaptable, I guess?" and nonsensical traits like "Only humans come from a multi-biome world."
This book contains 21 scenarios, from a galaxy where humans are the only bipeds to a fantasy world where humans were the first to discover ironworking and jealously guard that secret against their rivals. The description for each scenario includes an explanation of its plausibility and some of the scenario's implications.
Humans Are Weird also includes general advice for coming up with more scenarios on your own.