Why not? I worked on an electronics assembly line for a while doing electro-mechanical assembly. I enjoyed it and got satisfaction out of creating a physical product. It was kind of fun, not too stressful, sometimes monotonous, but also not too difficult. And after 8 hours I went home and didn't have to think about it until the next day.

I'm not saying that everyone enjoys that, or that we should keep those jobs around because I found it fun. But don't assume that just because a job seems menial to you that it must be horrible for everyone who's doing it.