That morning/evening chart at the end is kind of worthless in how vague it is. I mean, it's very low-resolution approximation of a normal distribution, without

That morning/evening chart at the end is kind of worthless in how vague it is. I mean, it's very low-resolution approximation of a normal distribution, without telling me anything about what it means to be a morning or evening person, or what distinguishes "moderate" from "extreme".