Eliot calls her crazy. Hardison does too. Sophie doesn't, but she thinks it. Parker has no idea what Nate thinks about her, but he probably thinks she's crazy too. Most people do. It doesn't bother Parker, but it's nothing she likes either.
Tara calls Parker 'my insane girl', when they're alone sometimes, lying in bed together, or eating breakfast. From anyone else insane would be an insult, but coming from Tara it's an endearment.