Service-to-Others (STO) means to think about others 50% of the time.
Service-to-Self (STS) means to think about the self 95% of the time. What is generally considered good most often corresponds to STO.
The terms are however laden with a baggage of subjectivity and what is good for one can be bad for another, thus these are easily misleading. The polarization to either STO/STS cannot be reduced to an external code of ethics only.