The phrase "He's at the chocolate teapot end of the competency scale" conveys a humorous and vivid image, suggesting that someone is entirely inept or useless at a particular task or in general. This metaphor relates to the book "A Long Way Down" by Nick Hornby, which explores the lives of four individuals who meet at a location for a suicide pact. The characters each have their own struggles, and the phrase encapsulates the idea that some people may feel completely out of their depth in life’s challenges.

In the context of Hornby's narrative, this idea highlights the varying degrees of competence and coping mechanisms among the characters. They each deal with their personal crises in different ways, and the comparison to a "chocolate teapot" suggests that, like the teapot, some may appear to have potential but ultimately lack the ability to function effectively. This reflects the underlying themes of vulnerability, despair, and the search for meaning found throughout the novel.