I would have thought that the number one use-case for a Service class would be to do 'stuff' in the database. In a different world you might want to call this the 'model'. However, I can find nowhere in the documentation that explains how to do this. The Service page in The Book is quite a lengthy read and I think it separates the bits most people will want (how to make a service and how to inject 'something') by a lot of more advanced discussion.

Anyway, as a reasonably new user, I would really have appreciated an early example of "Here's a simple Service that knows how to access the database". That is (unless I am missing something) completely absent. It had to go to StackOverflow to discover I needed to inject '@doctrine.orm.entity_manager' which is arcane to a newbie (and possibly non-newbies)