It seems like it’s relatively uncommon for people to quit after their first day of work. You spend so much time applying to jobs, and once you finally get one, you want to stay for at least a while to feel the thing out. Usually, the first few days at a new job are the most difficult, and once you get into the groove of things, it’s much smoother sailing.
However, there are some exceptions to this rule. Sometimes you enter a workplace that is so horrible, with such rancid vibes that you cannot stand to be there for another second. Other times, you come into a job where the job description is completely different from what you’re expected to do. It’s far worse to spend a month getting trained and leave after that than to quit while you’re ahead. People who quit on their first day of work shared their stories on Reddit, and many of them, I totally understand why they did it.