This.
ooOOooHH I am the ever-so-powerful, underworld princess, all-power-possessing, immortal, rare pup! You can't beat me! I possess every power in the world, I am immune to them, I am over 9000 years old and can't die!!!! I killed my whole pack because of my insanity!!!!
This is EXACTLY what I mean.
Honestly, I don't mind sad pasts or powers. It's just, THOSE ones who abuse the living days out of them.
I understand like, your parents died, or one parent died, since it happens often in real too, but going too overboard with it like "yeah, I killed mine because they grounded me for ten minutes" or "they were too weak and mortal" etc etc.
Powers... I don't mind them... It's just.... People who possess everything or abuse them.
Another thing that I've noticed is 'insane' people. Insanity doesn't mean going on rampages, killing everything. Insanity doesn't come from a small scratch this big bad guy caused. Insane doesn't mean op. Insane isn't the stories you read on creepy pasta wiki.
Insanity is a mental illness, and it's really different from that. I'd suggest you to look insanity up, its causes and what it does to you. There's few people that could actually pull off insane characters, and the key is: not what you see on the creepy pasta wiki. Most go by the popular one Jeff the Killer, which is SO unrealistic!
Speaking of mental illnesses, it's also a bit annoying when people give their characters some such as anxiety, depression, bipolar, etc etc. and don't do it correctly.
My point is- Don't make a character with sad past/powers/mental problems unless you experienced it yourself, or know how to PROPERLY roleplay it, know its symptoms, etc etc.