A-Cup Angst: To a minor degree, although she's a little irritated that her breasts aren't big enough to balance out her hips.
Ambiguous Disorder: She's got an anxiety disorder, as confirmed in the text, but whether it's social anxiety, OCD or another variant is never specified.
Betty and Veronica: Cath is the awkward, innocent Betty to her sister Wren's more outgoing and funny Veronica.
Brainy Brunette: Cath is quick-witted, observant and good at writing (at least fanfiction). She also has a head of curly brown hair.
Deadpan Snarker: Don't be fooled by the shy demeanour or nerdy glasses, Cath's been known to dole out her fair share of sarcasm where it's needed.
Love Interest: Although she doesn't put much effort into either her appearance or her conversational skills, all three of the male lead characters have had a thing for her at some point.
Mistaken for Gay: When she's about to tell her father that she's dropping out of college, he assumes she's coming out to him and tells her that he'd rather she be gay than pregnant.
The Friend Nobody Likes: Cath considered herself this back in high school, at least in comparison to the more people-oriented Wren.
Parental Abandonment: Arguably both her mother and father qualify. Her mother ran away from her family when the twins were nine, and though their dad struggled to pick up their pieces, he was mentally ill and occasionally ended up acting less like a parent than a child.
Polar Opposite Twins: With Wren. Cath is introverted while Wren is an extrovert; Cath is terrified of leaving home while Wren's excited to start a new adventure; Cath needs to learn how to take risks while Wren has trouble staying out of imminent danger.
Ethical Slut: Though Wren's said to have been with countless boys in the past, she's a loyal friend to Cath (despite her temperament) and far from being a bad person.
Polar Opposite Twins: With Cath. Cath is introverted while Wren is an extrovert; Cath is terrified of leaving home while Wren's excited to start a new adventure; Cath needs to learn how to take risks while Wren has trouble staying out of imminent danger.