|“||If you DARE touch my lip gloss, I'll use your arms as toothpicks and tell on you!||”|
Sierra is a manipulative, arrogant, and spoiled young girl. In PC Guy's words, she is "ten times worse than Stanley on his worst day". Her main trait is how much she loves to snitch on other people, even if they aren't doing any wrongdoings. She has quite a short temper and won't hesitate to yell at just about anybody, including her own father.
- Sierra's favorite meal is a peanut butter and jelly sandwich with the crusts cut off, macaroni and cheese that has been cooked for approximately 1 hour 15 minutes 37 seconds, carrot sticks arranged from smallest to largest, four snickerdoodle cookies and a box of apple juice.
- A common running gag in the series is when somebody makes the aforementioned meal incorrectly.
- Sierra has a dartboard in her bedroom that resembles Principal Walker.
- She does not physically appear in Season 3, although technically, the only episode she appears in is Dog Trouble, as her voice was heard through Bill's phone.
- She was supposed to appear in Crazy for Candy by singing at the Pearson apartment, but this was cut out for unknown reasons.