Eight o'clock in the morning refers to college students who have to struggle to get up for their first class at eight o'clock in the morning.
The early eight people actually evolved from migrant workers. Migrant workers often get up early and get greedy, holding a salary and doing several jobs. Although everyone has to go back to the painful life of punching cards after the break.
According to the internet, this stalk comes from college students, because junior high school students and senior high school students don't feel tired when they get up early, and some college students get tired of getting up early for eight classes, which leads to the ridicule stalk of "eight people in the morning, eight souls in the morning and eight classes in the morning".