He's tired or bored or both.
He probably feels a lot like an atheist trying to talk sense to a literal creationist.
This is a lot like wack-a-mole. I feel this way every day at work, and working on line from home.
On the other hand, Sisyphus was self aggrandizing and deceitful. That's why he was being punished. Reading the story, he was kind of a jerk. For the average person, the experience is more like something from Kafka.
Good answers, Gerald, Bertold, and especially Daniel. I think many, if not most, factory workers (and others) are Sisyphus-like. Every day, the same ol', same ol'. It's a living, but you're not getting anywhere. You feel frustrated, perhaps angry, resigned to your position in life.
Wikipedia explains the Sisyphus mythology in grand detail. You learn something every day!
Why don't I just stop? What's he gunna do, kill me?