that is meaningless semantics. both words have multiple meanings, when i said politicians serve corporations i meant that they are ultimately subservient to them because they get paid by them and their live style is contingent on this servitude and that is a system of control in this context both words refer to the same thing.
in the example of the waitress she is being controlled when u call them or tell them to get u a certain food u are controlling their actions control doesn't have to be absolute and it doent have to be forced.
a better example would be a social worker who helps people aka serves them but does not respond to them and are not controlled by the people they serve.
in the example of a prisoner there is control but no servitude sure, but it is trivial to think of an example where there is control and servitude like a serf, u know cuz world have different meaning and all.