The planet is tidally locked with the sun.

The physiology of the people who live in the light have evolved to need constant nourishment and never sleep. They have only a vague concept of time (things happen before other things can happen) and it doesn't play into their culture. No circadian rhythm or default cycle means they eat whenever they are hungry and it is not an important detail of when it occurs.

Large scale production projects and other massive undertakings require more managerial oversight to make sure things are done in the proper order. The society has a very "waterfall" production cycle because of this. coincidentally, the culture also has no concept of laziness. Due to physiology they cannot afford to sit down and rest for an hour or a week. Doing something like that simply causes that individual to die.