Insurance: insurance is an idea you pay for. You pay that if something gets bad, the insurer will pay, knowing there is little chance that stuff gets bad.

Education: outside of a piece of paper, and these days often even that doesn't exist, there isn't much about education that you can really touch

Knowledge and office work: your accountant, a secretary, a project manager are all very good representatives of service people. Again, yes they might move papers around, but most of their work is in ideas and knowledge that gets shared and transformed.