The thing I find most impressive is how the PCB assembly service manages to populate the PCB with hundreds of different parts of which some are barely larger than a corn of sand on a beach, and that not a single one ends up misplaced or mis-aligned after the reflow process.
Pick and place robots for electronics parts are mesmerizing to watch in operation. They move so fast it is almost impossible to see the actual placement of a part start-to-finish, you see parts 'appear'.
The thing I find most impressive is how the PCB assembly service manages to populate the PCB with hundreds of different parts of which some are barely larger than a corn of sand on a beach, and that not a single one ends up misplaced or mis-aligned after the reflow process.