You would have heard some people calling Wednesday as the Hump Day. If you have not known the reason behind it, it might have happened due to cultural differences. In some cultures, people have actually divided their workweek according to the shape of a hump. The hump shape is like a hill or mound and people feel like climbing up their workweek during the early days of a week while going down during the latter days of a week. They think that Wednesday is the middle of their workweek and forms the peak of the hump.
