Russian serfs might've revolted when they got the chance, but they were more or less psychologically normal until then. Their society adapts to not kill them all. (Or they all become alcoholics or something.)
That's an over simplification.
People could still have more free time than we do now[1], while their life could be more monotonous on some aspect, I believe an average office worker life today can be even more monotonous than what a serf life could be. You also have to consider labor alienation, which is a something that didn't exist so much before industrialization.
Most importantly, life commonly revolved around tight communities, while today most people live in individualist societies.
Individualism certainly has a larger impact on happiness than most modern convenience has.
- [1]: https://groups.csail.mit.edu/mac/users/rauch/worktime/hours_...
No, preindustrial ages weren't the hell they're made to be nor a golden age by any means. The same can be said of today. Stop playing defensive and think openly instead, there's lot we can improve by learning from the past.