With a design that encourages granularity, it's easy to make the mistake of assigning each service to a person. This can result in a developer taking ownership of service, feeling personally responsible for it, and often identifying with it. Some developers might take criticism of the service as a personal attack. Introducing changes might also be seen not as a technical decision, but a personal one.
Separation of services also leads to detachment. Developers lose sight of the system and focus on their own services. They stop trying to understand the other services and the system as a whole and choose to focus on their own service.