Coach Penny is a cranky and mean teacher most of the time. She is also rather arrogant and egotistical, thinking she is superior to everyone, and taking pride in putting down students (especially Ravi and Luke). She's incredibly strict as well.
She hates Jessie ever since she she wrote "Best Year Of My Life," because Jessie wrote a song about her perfect boyfriends, which makes the single gals feel bad. She also hates Harold, her ex-fiance who dumped her one month before their wedding and started dating the lunch-lady.