Go nuts man. I love interesting characters. Ones who will create a awesome dynamic between everyone else. For example, my character's going to be a massive snobby bitch so she's going to heckle the crap out of everyone.
Honestly, I'm looking more at personality. History isn't the biggest of deals for me. If you want to focus something, focus the roleplay sample. History rn is for me to kind of shuffle through what kind of person made this character. Because if I find someone who had a really sappy or super tragic backstory in a sue like way I can tell that the character is going to sue it up and make it annoying for everyone.