His example is a clock maker. At some point, a clock maker was a person who made every aspect of a clock. If we split the jobs up between someone making the cabinet, someone the clockwork, someone the face and hands etc, productivity will increase and more clocks can be made for less effort, and at higher quality. However it's not as fulfilling to create a component of a clock as it is to create the entire thing.
I think a better modern example is the building industry. Back in they day, people made their own houses - very labour intensively and not particularly well. But I wonder if there's much more rewarding and meaningful than literally building the house your family will live in?
With the the emergence of building as a trade, you get cheaper, higher quality houses. An individual builder still gets a ton of fulfillment knowing they built a house for someone they know to live in. As the trades become more and more specialized, there's less and less connection. Eventually you end up with someone working in a pre-fab factory making frames for a house they'll never see, for people they'll never meet.
It requires a level of comfort with abstraction to be OK with being so disconnected from actual outcomes. You either have to substitute in a secondary meaning ("I'm supporting my family") or be able to hold the whole picture in your head of how your job eventually contributes to an meaningful outcome.
