There might be some truth in that statement. I recalled visiting my elder sister and we had this discussion over dinner. She told me the story of her domestic help who hailed from the western part of the country. The help had just returned from her December holiday and brought so much foodstuff for my sister. She was elated. We ended up discussing her help’s jovial mood. We arrived to the conclusion that people from that part of the country had a higher tendency to happiness compared to us from the central part of the country.
I think happiness which entails contentment, joy, laughter, and kindness is influenced by a number of factors. One of them is the amount of responsibility placed upon a person. The more control a person has on their daily tasks, the happier they get. That is why, a casual worker may sleep better than a manager as they have more control over their day. Similarly, a domestic help is in control of their tasks, which they may enjoy easily compared to my sister who is a government employee as most of her daily tasks are unpredictable.
Another crucial factor is the issue of maintaining appearances. Most people from higher social classes have to work hard to maintain their lifestyles. On the other hand, people from the low social classes have little burden to maintain such appearances.
I will also use the analogy of a drug addict to further explain my point of view. A new drug user will only require a small amount of a drug to achieve a high compared to along term drug user. Thus, people from higher social classes may have to work harder to be happy, compared to their counterparts in the lower social classes.