Working any number of hours isn't "normal", it's a trade off between free time and money (for example, colleagues who work part time in order to sleep late) and a consequence of social pressure (e.g. competitive attitude) and practical constraints (e.g. keeping a shop open at constant and useful hours).

In some cases people want to work, to some extent, because their job is more pleasant than their free time activities, but it cannot be considered "normal".