I want a setting where there's a area of space known for destroying minds and causing insanity, a corrupting zone all other alien species avoid. One day a new species emerges with advances in space travel from that zone, it's humans. Due to that species evolving in that zone they're relatively resistant effects, and are able to survive where no other higher alien forms could. As a side effect, when humans interact with outside alien races, they're by comparison insane evil unpredictable creatures because the other races never evolved to survive within that influence. Entire sectors have meetings because oh fuck the humans keep peeking out like it's nothing and they're really nuts what do we do?
All of the curiosity, the evil, the cruelty, the kindness, shit no other species is ready to handle in such extremes so fast with almost no signs it's time to switch from the intergalactic schizo race who has a multitude of fake real mortal immortal gods who they all believe and don't believe in.
Sign me up, it's time to be a problem.