Many things that don't make sense in SU world like Gems somehow got life and other stuffs so in this list, I will give you 10 EXEMPLES that make no sense. (I know this is just a fiction and anythings can happened in a fiction even if it impossible)
1) Gemstones are only found in Earth. (They can be only find in Earth)Â
2) Gems can't have life (They are just rocks and if they do exist then they would eat and stuff like other aliens form other show. Also the diamonds's orgin is unexplained)Â
3) Humans don't have free will at all in SU (They think they have free will but they actaully don't. If they had free will then NASA would exist)Â
4) The diamonds are dumb. (They think that Humans are too weak and useless but they don't know that Military exist and they have powerful weapons that could destroyed them so easy) Â
5) Why Steven don't feel when his gemstone is stuck in his belly. (Steven don't feel anything when his gemstone is stuck in his belly and he don't know that Rose Quartz can be restore if he go to into a surgery to remove his gemstone and cover the hole with a fake bellybutton. If Steven want to instead of the hard way)Â
6) Jasper and Eyeball are dumb. (They are too dumb to understand that Steven is not Rose Quartz even they know that gems CAN'T shapeshifted for TOO long like how Amethyst got tired when she was shapeshift as Jasper for too long. How the heck they forgot about this and yet they NEVER questioning Steven about this)Â
7) Why Agate is Stupid. (How did she forgot that Ruby and Sapphire need to wear their homeworld outfit, When she saw Ruby  and Sappire, She was FINE until she saw Garnet)Â
8) Why the Zoomens forgot their own life in Earth (How come they don't know about Emotions and other stuffs like their own life on Earth, Useless Blue Diamond wipes all their memories with her special powers and no the Human maker machine  is a very dumb idea and if they have those then the zoo would have million of humans in it)Â
9) Why didn't the diamonds colonzied the rest of the solar system. (How come they didn't colonzies those planets like Mars and Venus. Steven once told the rubies that Jasper about Neptune and then they return to earth to yell at the crystal gems for lying without telling the diamonds about Neptune) Â
10) Why didn't the rubies inform at the diamonds about the crystal gems? (Did they forgot to or they think they know that the CG still exist.Â
I may add mores once i think about it.