A thing about humans that would freak out aliens. We get fat.
No, hear me out. Earth is so damn hazardous, that we evolved ridiculously overpowered energy storage. We can go without food for days, even weeks, because sometimes our ancestors had to. And now we’ve got plenty of food, but our energy storage system is still so overclocked that we can develop layers of fuel so thick it’s like armour.
Imagine all those stick-thin aliens being scared stiff because humans are so good at eating everything our bodies store ALL OF IT.