I would bet the majority of even this forum of debbie-downers genuinely enjoy their job.
What does enjoying your job mean?
Most people enjoy feeling useful. Most people would want to do something productive even if they didn't have to. Most people appreciate opportunities to demonstrate skills they have learned or expertise they have gained. Most people like being rewarded. Most people also have things about their jobs they don't like, things that are tedious or annoying, things that are stressful or (in some cases) actively traumatizing. Very few people like or hate everything about their job, most people are somewhere in the middle.
One thing that is generally true is that in the past people worked a lot less. Even medieval peasants, who we (somewhat correctly) think of as brutally oppressed, only worked about half the days of the year unless conditions were exceptionally bad. People also generally had more control over their working lives in the past. Roles were less specialized so people performed more varied labor. Work often incorporated opportunities to socialize or engage in recreation. Pre-industrial labour was often very hard physically, but it was also demonstrably freer in many ways.
Work has fundamentally changed under capitalism. We live in an economic system whose purpose is not to make us happy, but to extract maximum value from us at minimum cost, even if the result is that work is mechanistic, monotonous, excessive or highly pressured. The simple fact is, it doesn't matter if people enjoy their work or not, they don't have enough control over their lives or working conditions to do anything about it.
If the choice is between working and being unemployed, which is the reality for most people, then it's not much of a choice. If the choice is between working and living lives of incomprehensible, bacchanalian luxury while everyone else works
for you, I imagine the proportion of people who "enjoy their job" would take a pretty substantial nosedive.